lab 6
TRANSCRIPT
UNIVERSITI TUN HUSSEIN ONN MALAYSIA
FACULTY OF MECHANICAL AND MANUFACTURING ENGINEERING
BTI 10202: COMPUTER PROGRAMMING
LAB 6 : Control Statements – Part 2 (Loops)
NAME : _____________________________MATRICS NO.: _______________ DATE : _____ MARK
Objectives: Students be able to develop a repetition statements or program by using the iteration
structure (loops).
i. while loop statement
ii. do…while loop statement
iii. for loop statement
Theory:
a. while
i. Syntax of while loop (one statement):
while (condition- Code to execute while the
condition is true)
{
Statement;
}
ii. Syntax of while loop (> one statement):
while(condition- repeated until becomes false)
{
Statement 1;
Statement 2;
:
:
Statement n;
}
Example:
/*Total up from marks 1 to marks 5.*/
while(count<=5) /* count from 1 until 5*/
{
printf(“Key in the marks (%d) =”,
count);
scanf(“%d”, &marks);
total=total+marks; /*add the marks
one by one*/
count+=1; /*add the count*/
}
b. do…while loops are useful for things that want to loop at
least once
Notice that the condition is tested at the end of the block
instead of the beginning, so the block will be executed at
least once
Syntax of do…while loop:
do
{
Statement 1;
Example:
/* Total up from marks 1 until marks 5*/
do
{
printf(“Key in the
marks(%d)=”,count);
scanf(“%d”, &marks);
total=total+marks; ‘* total up the
marks one by one*/
1
:
:
Statements n;
}
while(condition);
count+=1; /*add count*/
}
while(count<=5); /*repeat until count
reach 5*/
c. for condition tells the program that while the conditional
expression is true the loop should continue to repeat
itself.
Syntax of for loop:
for(initial value; condition; update counter)
{
Statement(s);
}
Example:
/*Total up from marks 1 until marks 5*/
for(count=1;count<=5;count+=1)
/*can write as ++count*/
{
printf(“key in the
marks(%d)=”,count);
scanf(“%d”, &marks);
total=total+marks; /* total up the
marks one by one*/
}
Flowchart for loop structures
d. Nested loops
Example:
#include<stdio.h>
#include<conio.h>
main()
{
int row,column,num;
do
2
{
printf(“\nEnter the number of row of your triangle (1-30 only):\n”);
scanf(“%d”,&num);
}
while(num<=0||num>30); /*cannot more than 30 or less than 0*/
printf(“Your triangle\n”);
for(row=1;row<=num;++row)
{
printf(“\n”);
for(column=1;column<=(row*2-1);column++)
{
printf(“*”);
}
}
getch();
}
Exercise:
1. What is the output of following ‘for’ loop source code?
#include<stdio.h>
#include<conio.h>
main()
{
int i;
printf("This is a for loop\n");
for(i = -5; i <= 0; i = i +1)
printf("%d ", i);
getch();
}
3
Output
2. Rewrite the ‘for’ loop program in Exercise 1 using ‘while’ loop statement to give the same
output.
3. Type the example source code for the nested loops (at theory: d section) and observe the
output. Explain the program in detail.
Output:
4
While statement
5