Punuptech

Nested loop is one loop inside another loop.
Example

#include<stdio.h>
main()
{
int i,j;
for(i=1;i<=4;++i)
{
printf(”%d\n”,i);
for(j=1;j<=i;++j)
printf(”%d “,j);
}
}
Output
1
1 2
1 2 3
1 2 3 4

here,an inner for loop is written inside the outer for loop. For every value of i, j takes the value from 1 to i and then value of i is incremented and next iteration of outer loop starts ranging j value from 1 to i.

written by Shweta

The for allows us to specify three things about a  loop in single line :

1. Setting a loop counter to an initial value.
2. Test conditions.
3. Increasing the value of loop counter each time the program segment within the loop has been executed.

Syntax

for (initialize counter ; test counter; increment counter)

{

}

Concept of execution of For loop

• Initialization,testing and incrementation part of for loop can be replaced by any valid expression.

Example

• for (i=10; i ; i–)

         printf(”%d”,i);

• for (i<4; j=5; j=0)

         printf(”%d”,i);

• for (i=1; i<=10;printf(”%d”,i++))

         ;

written by Shweta

Syntax:

do

{

.

.

.

}while(this condition is true);

The only difference between while and do-while is that do-while would execute its statements at least once,even if the condition fails for the first time.

Example

main()

{

do

{

printf(”Hello”);

}while(4<1)

}

printf  would be executed once, since first  the body of the loop is executed and then condition is tested.

written by Shweta