While Statement

The while statement in C is used to create a loop that repeatedly executes a block of code as long as a given condition is true. It's one of the most basic forms of looping in C.

while Syntax

while (condition) {
    // Code to execute while the condition is true
}

How It Works:

• The condition is evaluated before each iteration.
• If the condition is true (non-zero), the code inside the loop executes.
• After executing the loop body, the condition is re-evaluated.
• The loop continues until the condition becomes false (zero).

#include <stdio.h>
int main() {
    int i = 0;
    while (i < 5) {
        printf("%d\n", i);
        i++;
    }
    return 0;
}

#include <stdio.h>
int main() {
    int n, sum = 0, i = 1;
    printf("Enter a positive integer: ");
    scanf("%d", &n);

    while (i <= n) {
        sum += i;  // Add i to the sum
        i++;
    }

    printf("The sum of first %d natural numbers is %d\n", n, sum);

    return 0;
}

#include <stdio.h>
int main() {
    while (1) {
        printf("This is an infinite loop.\n");
    }
    return 0;
}

Key Points:

• Condition:
  • The condition is checked at the beginning of each iteration.
  • If the condition is initially false, the loop body is skipped.
• Infinite Loop:
  • Be careful with infinite loops. Ensure there's a mechanism to break out if necessary.
• Variables:
  • Use variables within the condition to control the loop (e.g., counters or flags).
• Avoid Common Errors:
  • Ensure the condition will eventually become false to prevent unintended infinite loops.