编辑代码

#include <stdio.h>
int main () 
{
    int Fact (int tree);

    int tree,sum;
    printf("\n请输入要求阶乘数\n<<< ");

    scanf ("%d",&tree);

    sum = Fact(tree);
	return 0;
}

int Fact(int tree)
{
    int sum = 1;
    
    if (tree == 1 || tree == 0)
    {
        sum = 1;
    }
    else if(tree < 0)
    {
        printf("\n****负数没有阶乘！****\n");
    }
    else
    {
        sum = Fact(tree-1)*tree;
        printf("\n%d!=%d\n",tree,sum);
    }
    return sum;
}