Recursive function call example

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
/**
 * Recursive programming example
 * @Author:     Shaun B
 * @Version:    1.0.0.1
 * @Date:       2012-08-10
 **/
int main();
unsigned long factorial(unsigned long);
unsigned long number = 0;
char key = 0;
int main()
{
    // This line of code might not work with Visual Studio, but it's okay
    // with Code::Blocks -
    system("cls");
    // User prompts:
    printf("This is an example of recursive programming\n");
    printf("Please enter a number between 1 and 12 to \n");
    printf("see its' factorial value,\n");
    printf("or type 0 (zero) to exit.\n");
    printf("C:\\>");
    scanf("%d", &number);
    // Checks for zero to exit:
    if(number == 0)
    {
        return 0;
    }
    // Calls the recursive function factorial, sending the entered number to it:
    printf ("And the answer is %d\nPress enter to start again\nor space and enter to exit.\n",factorial(number));
    // Clears keyboard buffer:
    getchar();
    // Stores next key press into a variable:
    key = getchar();
    // Checks if it's space:
    if(key==32)
    {
        return 0;
    }
    else
    {
        // Restarts the program:
        number = 0;
        main();
    }
}
unsigned long factorial(unsigned long n)
{
    // Break case:
    if (n == 1)
    {
        return n;
    }
    else
    {
        // Calls function recursively:
        return n * factorial ( n-1 );
    }
}