Question

What is wrong with this code? The while loop continues to run even if a ‘1’ or ‘2’ is typed.

#include "stdio.h"

void helper(void);
int main() {
    int s;

    scanf("%d", &s);

    while(s!=1 || s!=2) {
        helper();
        scanf("%d", &s);
    }

    return 0;
}

void helper(void) {
    printf("Please use 1 or 2 as option");
}

Answer 1

Any number is either not equal to one or not equal to two: you can be certain of that 🙂

What you probably wanted to write was &&.

while(s!=1 && s!=2) {
}