第五階段—函數—幾個特殊函數—遞歸函數：使用遞歸求5的階乘

#include<stdio.h>

int fibo(int n)
{
    if( n < 0)
    {
        return -1;
    }else if(n == 0 || n == 1){
        return 1;
    }
    int ret = n*fibo(n-1);
    return ret;
}

int main(int argc, const char *argv[])
{
    int n = 0;
    printf("please input:");
    scanf("%d",&n);
    
    printf("%d ",fibo(n));
    
    printf("\n");
    return 0;
}