GETTING STARTED Getting Started Getting Started to Success Session 1.
Getting Started With Coding
description
Transcript of Getting Started With Coding
Getting Started With Coding
By:
Mr. Baha Hanene
Chapter 3
2
Learning OutcomesWe will cover the learning outcome 02 in this chapter i.e.
Use basic data-types and input / output in C programs. (L02)
3
ContentsIntroduction to ProgrammingStages & Steps of Writing ProgramsPreprocessor DirectivesMain FunctionOutput StatementVariables in CAssignment StatementsSample ProgramsReferences
4
Programming IntroductionA language which is used to instruct
computer to perform different tasks according to the requirements.
Every programming language has following basic things.
Declarations Assignments Control Statements I/O (Input/output)
Statements
5
Programming IntroductionAny programming language consists of its
own keywords and syntax rules that distinguishes it from other programming languages.
If you want to program in a specific language, you need the compiler of this specific language.
For example, C language compiler translates programs written in C language to machine language.
6
Programming StyleKeep it clear & simpleKeep it shortThink it through in advance
7
Stages & Steps of Writing ProgramsSpecificatio
nDesign
Coding
Testing
Documentation
Maintenance
8
Preprocessor DirectivesIn C programming whenever you see lines
that begin with a in column 1 are called preprocessor directives (commands)
The #include<stdio.h> directive allows the processor to include basic Input / Output in the program at this point.
#
9
stdio.hThis header file we include in all programs
where we need to use basic I/O commands e.g.
printf(“”); scanf(“”);Some functions are very difficult and very
long to write, these header files contains built in functions to provide us help in writing the programs.
10
void main( )Every C program has a main function, this is
where the program starts it’s execution, as this is the first function to execute in the whole c program.
The reserved word “void” shows that this function will not return any value.
Each C program can contain only one main function e.g.void main()
11
Function BodyA left brace (curly bracket) -- { -- begins the
body of every function. A corresponding right brace -- } -- ends the function body.
void main(){
…………
}BO
DY
Main Function
12
printf(“”);This line is called a C statementprintf(“”); is a function which is used to instruct
computer to display something on computer screenAll text, special symbols you will type inside
printf(“”); between the double quotations i.e. “……..” will be displayed as it is on your computer screens except few commands like /t, /n, %i etc.e.g.
printf(“Welcome at KIC”);
Notice that the above line ends with a Semicolon ; (every C statement ends with a semicolon i.e. ;)
13
Sample Program Explanation#include<stdio.h>
void main()
{
printf(“Hello to programming”);printf(“\n Welcome at KIC”);printf(“\t at Fall 2010/11”);
}
Header File used for Input / Output
Main Function Necessary to start any C program
Output Statement used to display on screen
Function Start
Function End
\t\n Start New
Line
Give Space between text
14
Variables in CIn computer programming, a variable is a
name given to some known or unknown quantity or value, for the purpose of allowing the name to be used independently of the value it represents
[Data Type] [Variable Name] ;Data Types: In C programming there are more data types but we generally use the following data types. (more details in next chapter)
1. int2. float 3. char
15
Variables in CVariable Name: You can give any name to the
variables in c but there are few rules for writing variable names. (A-Z) The first character must be a letter Space is not allowed between names of identifiers (&*^%$#@) Special symbols are not allowed in
identifier names - Hyphens are not allowed in identifier names
however underscores _ can be used (int, float, private etc.) The reserve words are not
allowed in identifier names.
16
Variables in CSome valid identifiers / variable nameshello j9 box22a get_data bin3d4
countSome reserve words (can’t be used as
identifier):private else static int const float
17
Variables in Cvelocityfredatime-of-day inttax_ratex24xfirst value radio@4emp.
velocityfredatime_of_day INVALIDtax_ratex2x4first_value radio4emp
RIGHTRIGHTRIGHT
RIGHTRIGHTWRONG
WRONGWRONGWRONG
18
Variables in CHow & where we write variables in C
programming….?We usually declare all variables inside main
function for example:
#include<stdio.h>
void main(){ int avar ; int salary ; float percentage ;}
Data Type Variable Name
Semi Colon (every C statement ends with a semicolon ;)
19
Sample Program Multiple Variable Declaration
Any Questions
????
?????
Assignment
Statements
20
Assignment StatementsBefore using variables in assignment statements you
should define / declare them first e.g. int a;Assignment Statements
first_number = 35; second_number = 21; sum = first_number + second_number;
The first two statements assigns the values 35 and 21 to the variables first_number and second_number respecitively
The next statement assigns the sum of the two values to the variable sum.
21
Sample Program Header File
Main Function
Function Body
Variable Declaration
Assignment Statements
Screen Output
22
Displaying Variable ValueDo you see something different in normal
printf statements and these which we have seen in the last sample program???
What are these
things????
%d These are called Format Specifiers used to display the value stored in the variable i.e. Inside computer memory
23
Sample Program Output
24
The Logical FlowSource Program
CompileSyntax Error
OK
Object Code/ Program
Run Run-time Error
OK
ResultLogical Error
OK
ENDContinue
25
Referenceshttp://en.wikipedia.org