While Loop

Sometimes you need to repeat something over and over until a condition changes. That's a loop. The while loop is the simplest — it keeps going as long as its condition is true.

The while Loop

Check the condition first. If it's true, run the body. Then check again. Repeat until false.

#include 
int main() {
  int i = 1;
  while (i <= 5) {
    printf("Count: %d\n", i);
    i++;
  }
  return 0;
}
    

How Condition Checking Works

The condition is evaluated before each iteration. If it's false from the start, the body never runs. That's why while is called a pre-test loop.

#include 
int main() {
  int i = 10;
  while (i <= 5) {
    printf("This won't print\n");
    i++;
  }
  printf("Loop skipped because 10 > 5\n");
  return 0;
}
    

Infinite Loops

If the condition never becomes false, the loop runs forever. Sometimes intentional (game loops, servers), but usually a bug.

#include 
int main() {
  int i = 1;
  while (i > 0) {
    printf("This will go on forever...\n");
    i++;
  }
  return 0;
}