1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float ...
-
Upload
rosalyn-barrett -
Category
Documents
-
view
243 -
download
0
Transcript of 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float ...
![Page 1: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/1.jpg)
1
Numeric Types, Expressions, and Output
![Page 2: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/2.jpg)
2
Chapter 3 Topics
Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric Types Implicit Type Coercion and Explicit Type Conversion Calling a Value-Returning Function Using Function Arguments Using C++ Library Functions in Expressions Calling a Void Function C++ Manipulators to Format Output String Operations length, size, find, substr
![Page 3: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/3.jpg)
3
C++ Data Types
structured
array struct union class
address
pointer reference
simple
integral enum
char short int long bool
floating
float double long double
![Page 4: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/4.jpg)
4
C++ Simple Data Types
simple types
integral floating
char short int long bool enum float double long double
unsigned
![Page 5: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/5.jpg)
5
Standard Data Types in C++
Integral Types• represent whole numbers and their negatives• declared as int, short, or long
Floating Types• represent real numbers with a decimal point• declared as float, or double
Character Type• represents single characters• declared as char
![Page 6: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/6.jpg)
6
Samples of C++ Data Values
int sample values 4578 -4578 0
float sample values95.274 95. .265
9521E-3 -95E-1 95.213E2
char sample values
‘B’ ‘d’ ‘4’ ‘?’ ‘*’
![Page 7: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/7.jpg)
7
Integral Types
The data types char, short, int, and long are intended
to represent different sizes of integers.
The sizes are machine dependent.
For one particular machine, we might picture the sizes
this way.
char memory cell
short memory cell
int memory cell
long memory cell
![Page 8: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/8.jpg)
8
Integral Types ( Cont.)
We can also explicitly add the reserved
word unsigned to the data type name:
unsigned int
The unsigned integer value is assumed to
be only positive or zero.
![Page 9: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/9.jpg)
9
Scientific Notation
2.7E4 means 2.7 x 10 4 =
2.7000 =
27000.0
2.7E-4 means 2.7 x 10 - 4 =
0002.7 =
0.00027
![Page 10: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/10.jpg)
10
More About Floating Point Values
floating point numbers have an integer part and a fractional part, with a decimal point in between. Either the integer part or the fractional part, but not both, may be missing
EXAMPLES 18.4 500. .8 -127.358
alternatively, floating point values can have an exponent, as in scientific notation--the number preceding the letter E doesn’t need to include a decimal point
EXAMPLES 1.84E1 5E2 8E-1 -.127358E3
![Page 11: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/11.jpg)
11
Division Operator
the result of the division operator depends on the type of its operands
if one or both operands has a floating point type, the result is a floating point type. Otherwise, the result is an integer type
Examples11 / 4 has value 211.0 / 4.0 has value 2.7511 / 4.0 has value 2.75
![Page 12: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/12.jpg)
12
Main returns an int value tothe operating system
//***************************************************************************// FreezeBoil program// This program computes the midpoint between// the freezing and boiling points of water//***************************************************************************#include < iostream >
using namespace std;
const float FREEZE_PT = 32.0 ; // Freezing point of waterconst float BOIL_PT = 212.0 ; // Boiling point of water
int main ( ){ float avgTemp ; // Holds the result of averaging
// FREEZE_PT and BOIL_PT
![Page 13: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/13.jpg)
13
Function main (Cont.)
cout << “Water freezes at “ << FREEZE_PT << endl ; cout << “ and boils at “ << BOIL_PT << “ degrees.” << endl ;
avgTemp = FREEZE_PT + BOIL_PT ; avgTemp = avgTemp / 2.0 ;
cout << “Halfway between is “ ; cout << avgTemp << “ degrees.” << endl ;
return 0 ;}
![Page 14: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/14.jpg)
14
Modulus Operator
the modulus operator % can only be used with integer type operands and always has an integer type result
its result is the integer type remainder of an integer division
EXAMPLE11 % 4 has value 3 because
)4 11
R = ?
![Page 15: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/15.jpg)
15
More C++ Operators
8
int age;
age = 8;
age = age + 1;
age
9
age
![Page 16: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/16.jpg)
16
PREFIX FORMIncrement Operator
8
int age;
age = 8;
++age;
age
9
age
![Page 17: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/17.jpg)
17
POSTFIX FORM Increment Operator
8
int age;
age = 8;
age++;
age
9
age
![Page 18: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/18.jpg)
18
Decrement Operator
100
int dogs;
dogs = 100;
dogs--;
dogs
99
dogs
![Page 19: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/19.jpg)
19
Which Form to Use?
when the increment (or decrement) operator is used in a “stand alone” statement solely to add one (or subtract one) from a variable’s value, it can be used in either prefix or postfix form
dogs-- ; --dogs ;
USE EITHER
![Page 20: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/20.jpg)
20
BUT...
when the increment (or decrement) operator is used in a statement with other operators, the prefix and postfix forms can yield different results
WE’LL SEE HOW LATER . . .(In Chapter 10)
![Page 21: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/21.jpg)
21
What is an Expression in C++?
An expression is a valid arrangement of variables, constants, and operators.
in C++ each expression can be evaluated to compute a value of a given type
the value of the expression
9.3 * 4.5 is 41.85
![Page 22: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/22.jpg)
22
Operators can be
unary involving 1 operand - 3
binary involving 2 operands 2 + 3
ternary involving 3 operands later
![Page 23: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/23.jpg)
23
Some C++ Operators
Precedence Operator Description Higher ( ) Function call
+ Positive
- Negative
* Multiplication
/ Division % Modulus (remainder)
+ Addition
- Subtraction
Lower = Assignment
![Page 24: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/24.jpg)
24
Precedence
higher Precedence determines which operator is applied first in an expression having several operators
![Page 25: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/25.jpg)
25
Associativity
left to right Associativity means that in an expression having 2 operators with the same priority, the left operator is applied first
in C++ the binary operators * , / , % , + , - are all left associative
expression 9 - 5 - 1 means ( 9 - 5 ) – 1=4-1=3doesn’t mean 9 - ( 5 - 1) = 9 – 4 = 5
![Page 26: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/26.jpg)
26
7 * 10 - 5 % 3 * 4 + 9means (7 * 10) - 5 % 3 * 4 + 9
70 - 5 % 3 * 4 + 970 - (5 % 3) * 4 + 9 70 - 2 * 4 + 9 70 - ( 2 * 4 ) + 9 70 - 8 + 9
( 70 - 8 ) + 9 62 + 9
71
Evaluate the Expression
![Page 27: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/27.jpg)
27
Parenthesesparentheses can be used to change the usual
orderparts in ( ) are evaluated firstevaluate (7 * (10 - 5) % 3) * 4 + 9
( 7 * 5 % 3 ) * 4 + 9 ( 35 % 3 ) * 4 + 9
2 * 4 + 9 8 + 9 17
![Page 28: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/28.jpg)
28
Mileage Program
/* This program computes miles per gallon given four amounts for gallons used, and starting and ending mileage. Constants: The gallon amounts for four fillups. The starting mileage.
The ending mileage.
Output (screen) The calculated miles per gallon.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/
#include <iostream>
using namespace std;
![Page 29: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/29.jpg)
29
C++ Code Continued
const float AMT1 = 11.7 ; // Number of gallons for fillup 1const float AMT2 = 14.3 ; // Number of gallons for fillup 2 const float AMT3 = 12.2 ; // Number of gallons for fillup 3 const float AMT4 = 8.5 ; // Number of gallons for fillup 4
const float START_MILES = 67308.0 ; // Starting mileageconst float END_MILES = 68750.5 ; // Ending mileage
int main( ){
float mpg ; // Computed miles per gallon
mpg = (END_MILES - START_MILES) / (AMT1 + AMT2 + AMT3 + AMT4) ;
![Page 30: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/30.jpg)
30
Main returns an int value tothe operating system
cout << “For the gallon amounts “ << endl ;cout << AMT1 << ‘ ‘ << AMT2 << ‘ ‘ << AMT3 << ‘ ‘ << AMT4 << endl ;
cout << “and a starting mileage of “ << START_MILES << endl ;
cout << “and an ending mileage of “ << END_MILES << endl ;
cout << “the mileage per gallon is “ << mpg << endl ;
return 0;}
![Page 31: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/31.jpg)
31
Declarations for Numeric Types
Named Constant Declarations
const float PI=3.14159;
const float E=2.71828;
const int MAX_SCORE=100;
const int MIN_SCORE= -100;
const char LETTER=‘W’;
const string NAME=“Elizabeth”;
Constant Declaration
![Page 32: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/32.jpg)
32
Declarations for Numeric Types (Cont.)
Given the declaration
int num;
int alpha;
float rate;
char ch;
The following are appropriate assignment statement:
Variable Expression
alpha= 2856;
rate= 0.36;
ch= ‘B’;
num= alpha;
Variable Declaration
In each of these assignment statements, the data type of the expression matches the data type of the variable to which it is assigned.
![Page 33: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/33.jpg)
33
Variable = Expression
first, Expression on right is evaluatedthen the resulting value is stored in the
memory location of Variable on left
NOTE: An automatic type coercion occurs after evaluation but before the value is stored if the types differ for Expression and Variable
Assignment Operator Syntax
![Page 34: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/34.jpg)
34
What value is stored?
float a;
float b;
a = 8.5;
b = 9.37;
a = b;
a
b
a
b
8.5
9.37
?
?
![Page 35: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/35.jpg)
35
What is stored?
? float someFloat;
someFloat
someFloat = 12; // causes implicit type conversion
someFloat
12.0
![Page 36: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/36.jpg)
36
What is stored?
? int someInt;
someInt
someInt = 4.8; // causes implicit type conversion
someInt
4
![Page 37: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/37.jpg)
37
Type Casting is Explicit Conversion of Type
int(4.8) has value 4
float(5) has value 5.0
float(7/4) has value 1.0
float(7) / float(4) has value 1.75
![Page 38: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/38.jpg)
38
Some Expressionsint age;
EXAMPLE VALUEage = 8 8- age - 85 + 8 135 / 8 06.0 / 5.0 1.2float ( 4 / 8 ) 0.0float ( 4 ) / 8 0.5cout << “How old are you?” coutcin >> age cincout << age cout
![Page 39: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/39.jpg)
39
What values are stored?
float loCost;
float hiCost;
loCost = 12.342;
hiCost = 12.348;
loCost = float (int (loCost * 100.0 + 0.5) ) / 100.0;
hiCost = float (int (hiCost * 100.0 + 0.5) ) / 100.0;
![Page 40: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/40.jpg)
40
Values were rounded to 2 decimal places
12.34
hiCost
12.35
loCost
![Page 41: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/41.jpg)
41
Function Concept in Math
f ( x ) = 5 x - 3
When x = 1, f ( x ) = 2 is the returned value.
When x = 4, f ( x ) = 17 is the returned value.
Returned value is determined by the function definition and by the values of any parameters.
Name of function
Parameter of function
Function definition
![Page 42: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/42.jpg)
42
Functions
every C program must have a function called main
program execution always begins with function main
any other functions are subprograms and must be called
![Page 43: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/43.jpg)
43
Function Calls
one function calls another by using the name of the called function together with ( ) containing an argument list
a function call temporarily transfers control from the calling function to the called function
![Page 44: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/44.jpg)
44
What is in a block?
{
0 or more statements here
}
![Page 45: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/45.jpg)
45
Every C++ function has 2 parts
int main ( ) heading{
body block
return 0;
}
![Page 46: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/46.jpg)
46
Shortest C++ Program
int main ( )
{
return 0;
}
type of returned value name of function
![Page 47: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/47.jpg)
47
What is in a heading?
int main ( )
type of returned valuename of function
says no parameters
![Page 48: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/48.jpg)
48
More About Functions
it is not considered good practice for the body block of function main to be long
function calls are used to do tasks
every C++ function has a return type
if the return type is not void, the function returns a value to the calling block
![Page 49: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/49.jpg)
49
Where are functions?
located in libraries
OR
written by programmers
![Page 50: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/50.jpg)
50
HEADER FILE FUNCTION EXAMPLE VALUE OF CALL
fabs(x) fabs(-6.4) 6.4
<cmath> pow(x,y) pow(2.0,3.0) 8.0
<cmath> sqrt(x) sqrt(100.0) 10.0
<iomanip> setprecision(n) setprecision(3)
<cmath> log(x) log(2.0) .693147
sqrt(x) sqrt(2.0) 1.41421
<cstdlib> abs(i) abs(-6) 6
![Page 51: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/51.jpg)
51
Write C++ Expressions for
The square root of b2 - 4ac
sqrt ( b * b - 4.0 * a * c )
The square root of the average of myAge and yourAge
sqrt ( ( myAge + yourAge ) / 2 )
![Page 52: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/52.jpg)
52
Program with Several Functions
Main function
Square function
Cube function
![Page 53: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/53.jpg)
53
Program with Three Functions
#include <iostream>
int Square( int ); // declares these functionsint Cube( int );
using namespace std ;
int main( ){ cout << “The square of 27 is “
<< Square(27) << endl; // function call
cout << “The cube of 27 is “ << Cube(27) << endl; // function call
return 0;}
![Page 54: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/54.jpg)
54
Rest of Program
int Square( int n ) // header and body here{ return n * n;}
int Cube( int n ) // header and body here{ return n * n * n;}
![Page 55: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/55.jpg)
55
Function Call
a function call temporarily transfers control to the called function’s code
when the function’s code has finished executing, control is transferred back to the calling block
![Page 56: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/56.jpg)
56
FunctionName ( Argument List )
The argument list is a way for functions to communicate with each other by passing information.
The argument list can contain 0, 1, or more arguments, separated by commas, depending
on the function.
Function Call Syntax
![Page 57: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/57.jpg)
57
A void function call stands alone
#include <iostream>
void DisplayMessage ( int n ) ; // declares function
int main( ){ DisplayMessage( 15 ) ; //function call cout << “Good Bye“ << endl ;
return 0 ;}
![Page 58: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/58.jpg)
58
A void function does NOT return a value
// header and body here
void DisplayMessage ( int n ) { cout << “I have liked math for “ << n << “ years” << endl ;}
![Page 59: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/59.jpg)
Two Kinds of Functions
Always returns a single value to its caller and is called from within an expression.
Never returns a value to its caller, and is called as a separate statement.
Value-Returning Void
![Page 60: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/60.jpg)
60
<< is a binary operator
<< is called the output or insertion operator
<< is left associative
EXPRESSION HAS VALUE
cout << age cout
STATEMENT
cout << “You are “ << age << “ years old\n” ;
![Page 61: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/61.jpg)
61
<iostream> is header file
for a library that defines 3 objects
an istream object named cin (keyboard)
an ostream object named cout (screen)
an ostream object named cerr (screen)
![Page 62: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/62.jpg)
62
No I/O is built into C++
instead, a library provides input stream and output stream
Keyboard Screenexecutingprogram
istream ostream
![Page 63: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/63.jpg)
63
Manipulators
manipulators are used only in input and output statements
endl, fixed, showpoint, setw, and setprecision are manipulators that can be used to control output format
endl is use to terminate the current output line, and create blank lines in output
![Page 64: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/64.jpg)
64
Insertion Operator ( << )
the insertion operator << takes 2 operands
the left operand is a stream expression, such as cout
the right operand is an expression of simple type, or a string, or a manipulator
![Page 65: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/65.jpg)
65
Output Statements
SYNTAX (revised)
cout << Expression Or Manipulator
<< Expression Or Manipulator . . . ;
![Page 66: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/66.jpg)
66
Output Statements (Cont.)SYNTAX
These examples yield the same output.
cout << “The answer is” ;cout << 3 * 4 ;
cout << “The answer is ” << 3 * 4 ;
cout << Expression << Expression . . . ;
![Page 67: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/67.jpg)
67
Using ManipulatorsFixed and Showpoint
use the following statement to specify that (for output sent to the cout stream) decimal format (not scientific notation) be used, and that a decimal point be included (even for floating values with 0 as fractional part)
cout << fixed << showpoint ;
![Page 68: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/68.jpg)
68
Setprecision(n)
requires #include <iomanip> and appears in an expression using insertion operator (<<)
if fixed has already been specified, argument n determines the number of places displayed after the decimal point for floating point values
Setprecision remains in effect until explicitly changed by another call to setprecision.
![Page 69: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/69.jpg)
69
What is exact output?
#include <iomanip> // for setprecision( )#include <iostream>
using namespace std;
int main ( ){ float myNumber = 123.4587 ;
cout << fixed << showpoint ; // use decimal format // print decimal points
cout << “Number is ” << setprecision ( 3 ) << myNumber << endl ;
return 0 ;}
![Page 70: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/70.jpg)
70
OUTPUT
Number is 123.459
value is rounded if necessary to be displayed with exactly 3 places after the decimal point
![Page 71: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/71.jpg)
71
Manipulator setw
“set width” lets us control how many character positions the next data item should occupy when it is output
setw is only for formatting numbers and strings, not char type data
![Page 72: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/72.jpg)
72
Setw(n)
requires #include <iomanip> and appears in an expression using insertion operator (<<)
argument n is called the fieldwidth specification, and determines the number of character positions in which to display a right-justified number or string (not char data). The number of positions used is expanded if n is too narrow
“set width” affects only the very next item displayed, and is useful to align columns of output
![Page 73: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/73.jpg)
73
What is exact output?
#include <iomanip> // for setw( )#include <iostream>#include <string>
using namespace std;
int main ( ){ int myNumber = 123 ; int yourNumber = 5 ;
cout << setw ( 10 ) << “Mine” << setw ( 10 ) << “Yours” << endl;
cout << setw ( 10 ) << myNumber<< setw ( 10 ) << yourNumber << endl ;
return 0 ;}
![Page 74: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/74.jpg)
74
OUTPUT
each is displayed right-justified andeach is located in a total of 10 positions
12345678901234567890 Mine Yours 123 5
position
![Page 75: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/75.jpg)
75
What is exact output?#include <iomanip> // for setw( ) and setprecision( )#include <iostream>
using namespace std;
int main ( ){ float myNumber = 123.4 ; float yourNumber = 3.14159 ;
cout << fixed << showpoint ; // use decimal format // print decimal points
cout << “Numbers are: ” << setprecision ( 4 ) << endl << setw ( 10 ) << myNumber << endl
<< setw ( 10 ) << yourNumber << endl ;
return 0 ;}
![Page 76: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/76.jpg)
76
OUTPUT
each is displayed right-justified and rounded if necessary and each is located in a total of 10 positions with 4 places after the decimal point
Numbers are: 123.4000 3.1416
12345678901234567890
![Page 77: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/77.jpg)
77
float x = 312.0 ; float y = 4.827 ;
cout << fixed << showpoint ; OUTPUT
cout << setprecision ( 2 ) << setw ( 10 ) << x << endl ’’’’312.00
<< setw ( 10 ) << y << endl ; ’’’’’’4.83
cout << setprecision ( 1 ) << setw ( 10 ) << x << endl ’’’’’312.0
<< setw ( 10 ) << y << endl ; ’’’’’’’4.8
cout << setprecision ( 5 ) << setw ( 7 ) << x << endl 312.00000
<< setw ( 7 ) << y << endl ; 4.82700
More Examplesx
312.0
y
4.827
![Page 78: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/78.jpg)
78
HEADER MANIPULATOR ARGUMENT EFFECT FILE TYPE
<iostream> showpoint none displays decimal point
<iostream> fixed none suppresses scientific notation
<iomanip> setprecision(n) int sets precision to n digits
<iomanip> setw(n) int sets fieldwidth to n positions
<iostream> endl none terminates output line
![Page 79: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/79.jpg)
79
Additional string Operations
The length and size Functionsfunction length returns an unsigned
integer value that equals the number of characters currently in the string
function size returns the same value as function length
you must use dot notation in the call to function length or size
![Page 80: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/80.jpg)
80
Additional string Operations (Cont.)
The find Function function find returns an unsigned integer value
that is the beginning position for the first occurrence of a particular substring within the
string
the substring argument can be a string constant, a string expression, or a char value
if the substring was not found, function find returns the special value string::npos
![Page 81: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/81.jpg)
81
Additional string Operations (Cont.)
The substr Functionfunction substr returns a particular substring
of a string
the first argument is an unsigned integer that specifies a starting position within the string
the second argument is an unsigned integer that specifies the length of the desired substring
positions of characters within a string are numbered starting from 0, not from 1
![Page 82: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/82.jpg)
82
What is exact output?#include <iostream>#include <string> // for functions length, find, substr
using namespace std;
int main ( ){ string stateName = “Mississippi” ;
cout << stateName.length( ) << endl;
cout << stateName.find(“is”) << endl;
cout << stateName.substr( 0, 4 ) << endl;
cout << stateName.substr( 4, 2 ) << endl;
cout << stateName.substr( 9, 5 ) << endl;
return 0 ;}
![Page 83: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/83.jpg)
83
What is exact output? (Cont.)#include <iostream>#include <string> // for functions length, find, substr
using namespace std;
int main ( ){ string stateName = “Mississippi” ;
cout << stateName.length( ) << endl; // value 11
cout << stateName.find(“is”) << endl; // value 1
cout << stateName.substr( 0, 4 ) << endl; // value “Miss”
cout << stateName.substr( 4, 2 ) << endl; // value “is”
cout << stateName.substr( 9, 5 ) << endl; // value “pi”
return 0 ;}
![Page 84: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/84.jpg)
84
Map Measurement Case Study
You want a program to determine walking distances between 4 sights in the city. Your city map legend says one inch on the map equals 1/4 mile in the city. You use the measured distances between 4 sights on the map.
Display the walking distances (rounded to the nearest tenth) between each of the 4 sights.
![Page 85: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/85.jpg)
85
// *************************************************** // Walk program// This program computes the mileage (rounded to nearest// tenth of mile) for each of 4 distances, given map// measurements on map with scale of 1 in = 0.25 mile// ***************************************************
#include <iostream> // for cout, endl#include <iomanip> // For setprecision
using namespace std;
float RoundToNearestTenth( float ); // declare function
const float SCALE = 0.25; // Map scale (mi. per inch)
C++ Program
![Page 86: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/86.jpg)
86
C++ Code Continued
const float DISTANCE1 = 1.5; // First map distanceconst float DISTANCE2 = 2.3; // Second map distanceconst float DISTANCE3 = 5.9; // Third map distanceconst float DISTANCE4 = 4.0; // Fourth map distance
int main( ){ float totMiles; // Total of rounded miles float miles; // One rounded mileage
cout << fixed << showpoint // Set output format << setprecision(1);
totMiles = 0.0; // Initialize total miles
![Page 87: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/87.jpg)
87
// Compute miles for each distance on map
miles = RoundToNearestTenth( DISTANCE1 * SCALE );
cout << DISTANCE1 << “ inches on map is “ << miles << “ miles in city.” << endl;
totMiles = totMiles + miles;
miles = RoundToNearestTenth( DISTANCE2 * SCALE );
cout << DISTANCE2 << “ inches on map is “ << miles << “ miles in city.” << endl;
totMiles = totMiles + miles;
![Page 88: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/88.jpg)
88
// Compute miles for other distances on map
miles = RoundToNearestTenth( DISTANCE3 * SCALE );
cout << DISTANCE3 << “ inches on map is “ << miles << “ miles in city.” << endl;
totMiles = totMiles + miles;
miles = RoundToNearestTenth( DISTANCE4 * SCALE );
cout << DISTANCE4 << “ inches on map is “ << miles << “ miles in city.” << endl;
totMiles = totMiles + miles;
![Page 89: 1 Numeric Types, Expressions, and Output. 2 Chapter 3 Topics Constants of Type int and float Evaluating Arithmetic Expressions Declaration for Numeric.](https://reader030.fdocuments.us/reader030/viewer/2022033023/56649e915503460f94b97185/html5/thumbnails/89.jpg)
89
cout << endl << “Total walking mileage is “ << totMiles << “ miles.” << endl;
return 0 ; // Successful completion}
// ***************************************************
float RoundToNearestTenth ( /* in */ float floatValue)
// Function returns floatValue rounded to nearest tenth.
{ return float(int(floatValue * 10.0 + 0.5)) / 10.0;}