Lab 3 rAlternation l Multiple Alternative Decision l Nested If Statements rIteration l While Loop l...
21
Lab 3 Alternation Multiple Alternative Decision Nested If Statements Iteration While Loop For Loop Do Loop Note: Look at math.h (Appendix B AP13), and limits.h (Appendix B AP19). Read about C operators (Appendix C AP22).
-
date post
22-Dec-2015 -
Category
Documents
-
view
218 -
download
2
Transcript of Lab 3 rAlternation l Multiple Alternative Decision l Nested If Statements rIteration l While Loop l...
Lab 3 Alternation
Multiple Alternative Decision Nested If Statements
Iteration While Loop For Loop Do Loop
Note:
Look at math.h (Appendix B AP13), and limits.h (Appendix B AP19).
Read about C operators (Appendix C AP22).
Alternation
Definition : Alternative Steps to take according to a particular condition.
Exp1: You need to develop an algorithm to control the warning signs at the exits of major tunnels.
If road_status is slick , you will have to check the temperature. If It is higher than 0, you will display the message “Wet road”, otherwise, you will display “Icy road”.
If the road is not slick, you want to display the message “Drive carefully”.
Exp1 Solution
Specification of the problem:
The problem’s objective is to display a warning message given the road_status.
Analysis Input : road_status, temp. Output: warning message.
Start
Get road_status
If ((road_status ==‘S’) || (road_status ==‘s’) )
{ Get temp
if (temp>0)
{display « Wet Road»}
else
{display « Icy Road»}
Endif }
Else
{display «Drive Carefully»}
Endif
End
Algorithm:
Exp2: Write a condition that identifies single males between the ages 16 and 26 inclusive, and display the message “All Criteria Are Met”.
Exp3: Implement the following decision table using nested if statement. Assume that the wind speed is given as an integer.
Wind Speed (mph) Category below 25 not a strong wind 25-38 strong wind 39-54 gale 55-72 whole gale above 72 hurricane
Exp2 Solution
If ((marital_status == ‘S’)|| (marital_status == ‘s’))
{ if ((gender == ‘M’)|| (gender == ‘m’))
{ if ((age>=18)&&(age<=26))
display « All Criteria are Met»
endif}
endif
} endif
Exp3 Solution
Specification of the problem:
The problem’s objective is to display the Wind’s Category according to the Wind’s speed.
Analysis Input: Wind_speed. Output: Category message.
Start
Get Wind_speed
If (Wind_speed <=24)) {display « not a strong wind»}Else if(Wind_speed <=38) {display « strong wind»} Else if(Wind_speed <=54) {display « gale»} Else if(Wind_speed <=72) {display «whole gale»}Else {display «hurricane»} Endif
End
Algorithm
Iteration
Definition : Certain steps that got repeated while a given condition is true.
While loop (variable number of times)
For loop (fixed number of times)
Do loop (variable number of times)
While Loop
While Loop Example
Write an algorithm that calculates the sum of a collection of exam scores. (if the class is very large, the instructor may not know the number of students who took the exam). The program should work regardless of the class size (use the SENTINEL).
Exp4 Solution
Start
SENTINEL=-99
Sum=0
Get score
While (score != SENTINEL)
{ sum += score
diplay « Enter next score ( »Sentinel « to quit )»
Get score
} EndWhile
Display « The sum of scores is » sum
End
For Loop
For Loop Example
Compute n!
Precondition: n is greater or equal to 0.
Exp5 Solution
Specification of the problem:
The problem’s objective is to display the factorial of n.
Analysis Input : n. Output: factorial. Relevant formula: factorial = factorial * i
Algorithm
Start
Get n
factorial =1
For(i=n;i>1;i--)
{factorial = factorial * i}
EndFor
Display « The n factorial is » factorial
End
Do Loop (Post Loop)
Do Loop Example
Compute n! as long as the user wants.
Precondition: n is greater or equal to 0.
Exp5 Solution
Specification of the problem:
The problem’s objective is to display the factorial of different n as long as the user wishes.
Analysis Input : n, again. Output: factorial. Relevant formula: factorial = factorial * i
Solution
Start
do
{Get n
factorial =1
For(i=n;i>1;i--)
{factorial = factorial * i}
EndFor
Display « The n factorial is » factorial
Display « One more time ? (1 to continue – 0 to quit) »
Get again
} while (again==1)
End
Common Use of Do Loop
Testing the input
Do { Display « enter n>0 » Get n} while (n<=0)
