Answer:
For loop Version:
#include <stdio.h>
int main()
{
    int number, sum = 0;
    printf("Enter a positive integer: ");
    scanf("%d", &number);
    
    for (int i = 0; i <= number; i++) {
        if(number == 0)
            break;
        sum += number;
        
        printf("Enter a positive integer: ");
        scanf("%d", &number);
    }
    printf("Sum is: %d", sum);
    return 0;
}
- - - - -
While Loop Version:
#include <stdio.h>
int main()
{
    int number, sum = 0, i = 0;
    printf("Enter a positive integer: ");
    scanf("%d", &number);
    
    while (number != 0) {
        sum += number;
        
        printf("Enter a positive integer: ");
        scanf("%d", &number);
    }
    printf("Sum is: %d", sum);
    return 0;
}
Do-while Loop Version:
#include <stdio.h>
int main()
{
    int number, sum = 0, i = 0;
    
    do {
        printf("Enter a positive integer: ");
        scanf("%d", &number);
        
        sum += number;
        
    } while (number != 0);
    printf("Sum is: %d", sum);
    return 0;
}
Explanation:
- Initialize the variables
- Ask the user for the numbers until the user enters 0
-  Calculate and print the sum