Why am I getting " void value not ignored as it ought to be"?

Question

basically returning the value straight as "return pow((n%10),3) + arms(n/=10);" works but not passing it through another variable?

#include <stdio.h>
#include <math.h>
void arms(int n){
    int temp;
    if (n!=0){
        temp = pow((n%10),3) + arms(n/=10);
    }
    (temp==n)?printf("ARMS"):printf("NO ARMS");
}
int main() {
    arms(153);
    return 0;
}

Answer 1

arms is void which means that it does not return anything, yet you try to use it in your calculation:

temp = pow((n%10),3) + arms(n/=10);
                     ^^^^^^^^^^^^^^

This is not valid. The compiler can't add void to pow(%n%10,3) .

A void function doesn't return anything but you as a programmer can't use it and expect the compiler to do the work for you, which in this case would be to remove the call to arms :

temp = pow((n%10),3);