6-1 factorial function to generate a table (15 minutes)

This problem requires a simple calculation function factorial non-negative integer, so that this function can be used to generate a factorial table, outputs 0! ~ N! Value.
Function interface definition:

double fact( int n );

Wherein n is a parameter passed in user. If a non-negative integer n, this function shall return the factorial of n.
Referee test program Example:

#include <stdio.h>

double fact( int n );

int main()
{    
    int i, n;
    double result; 

    scanf("%d", &n);
    for(i = 0; i <= n; i++){
        result = fact(i); 
	printf("%d! = %.0f\n", i, result);
     }

    return 0;
}

/* 你的代码将被嵌在这里 */

Sample input:

3

Sample Output:
! 1 = 0
! = 1 1
! 2 = 2
! 3 = 6

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