While Loops

Simple C while loop

#include <stdio.h>

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

Interactive while loop

#include <stdio.h>

int main() {
    int num;
    
    printf("Enter numbers (0 to quit): ");
    scanf("%d", &num);
    
    while (num != 0) {
        printf("You entered: %d\n", num);
        printf("Enter another number (0 to quit): ");
        scanf("%d", &num);
    }
    
    return 0;
}

C while loop with simple counter

#include <stdio.h>

int main() {
    int i = 1;
    
    while (i <= 10) {
        printf("Count: %d\n", i);
        i++;
    }
    
    return 0;
}

C while loop processing array elements

#include <stdio.h>

int main() {
    int arr[] = {10, 20, 30, 40, 50};
    int size = sizeof(arr) / sizeof(arr[0]);
    int i = 0;
    
    while (i < size) {
        printf("Element %d: %d\n", i, arr[i]);
        i++;
    }
    
    return 0;
}

C while loop with interactive user input

#include <stdio.h>

int main() {
    int num;
    
    printf("Enter numbers (0 to quit): ");
    scanf("%d", &num);
    
    while (num != 0) {
        printf("You entered: %d\n", num);
        printf("Enter another number (0 to quit): ");
        scanf("%d", &num);
    }
    
    printf("Exiting...\n");
    return 0;
}

C while loop processing string characters

#include <stdio.h>
#include <string.h>

int main() {
    char str[] = "Hello World";
    int i = 0;
    
    while (str[i] != '\0') {
        printf("Character %d: %c\n", i, str[i]);
        i++;
    }
    
    printf("String length: %d\n", i);
    return 0;
}

C while loop reading file character by character

#include <stdio.h>

int main() {
    FILE *file;
    char ch;
    
    file = fopen("input.txt", "r");
    if (file == NULL) {
        printf("Error opening file\n");
        return 1;
    }
    
    while ((ch = fgetc(file)) != EOF) {
        printf("%c", ch);
    }
    
    fclose(file);
    return 0;
}

C while loop with do-while pattern

#include <stdio.h>

int main() {
    int num;
    
    do {
        printf("Enter a positive number: ");
        scanf("%d", &num);
        if (num <= 0) {
            printf("Please enter a positive number!\n");
        }
    } while (num <= 0);
    
    printf("You entered: %d\n", num);
    return 0;
}