Loops in C Language allow repeating execution of statements or blocks of code. There are two types of loops: pretest and posttest. A pretest loop (for and while loops) tests the condition before each iteration. A posttest loop (do-while loop) tests the condition after each iteration. The for loop has three parts - an initializer, condition, and incrementor - that control the loop execution. The while loop tests a condition before each iteration. The do-while loop tests a condition after each iteration.

1. Presented By: Prof. Muhammad Waseem
Loops in C Language

2.  Loop Statement are used to
repeat the execution of
statement or blocks.
 Two types of loop structure are:
 Pretest
 Posttest

3.  Pretest: Condition is tested before each iteration to
check if loop should occur.
 Example: For and While Loop
 Posttest: Condition is tested after each iteration to
check if loop should occur.
 Example: Do-While Loop

4. For Loop has three parts:
 Initializer is executed at start of loop.
 Loop condition is tested before iteration to decide whether
to continue or terminate the loop.
 Increment is executed at the end of each loop
iteration.

5. for( [initializor]; [condition]; [incrementor] )
<statement/block>;
Example: for(i=0; i<3; i++)
printf(“Hellon”);
Output:
Hello
Hello
Hello

6.  It has a loop condition only that is tested
before each iteration to decide whether to
continue or terminated the loop.
Syntax:
while(<condition>)
<statement/block>;

7. Example:
while(i=0;i<3;i++)
printf(“Hellon”);
Output
: Hello
Hello
Hello

8.  Do-While has a loop condition only that is tested after
each iteration to decide whether to continue with next
iteration or terminate the loop.
Syntax:
do
<statement/block>;
while(condition);

9. Example:
Do {
printf(“Hellon”);
} while(i<3)
Output
: Hello
Hello
Hello