invalid operands to binary * (have ‘int’ and ‘int *’)

Question

I am trying to find out the factorial of a number using recursion and passing the pointers as function arguments. But this error appears all the time. Debugers and Coders! I need your assistance with this.

The code

#include<stdio.h>

int *factorial(int *);
int value, p=0, q=1, x, tmp;

void main() {
int *result;
    puts("Enter the value::");
    scanf("%d",&value);

    result = factorial(&value);
    printf("\nThe Result is::%d\n", *result);
}
int *factorial(int *n) {
    if(*n == p || *n == q) {
        return(&q);
    }
    else {
        tmp = *n -1;
        *n *= (factorial(&tmp));
        return(n);
    }
}

The error:
error: invalid operands to binary * (have ‘int’ and ‘int *’)
   *n *= (factorial(&tmp));

Answer 1

This line :

*n *= (factorial(&tmp));

should be

*n *= *(factorial(&tmp));

however, be careful with this implementation because it is recursive, but uses pointers to globals.

Would the standard implementation not work for you?

int factorial(int n)
{
    if(n==0)
        return 1;
    else
        return factorial(n-1)*n;
}

With the standard, you need to prompt your user for non-negative values only.