#include<stdio.h>
long recursion (int n);
int main(void)                                                                           C:\Users\Lenovo\AppData\Local\Temp\ccIUDdP6.o        In function `main':
{
        int n;
        long result;
        printf("input a integer number:\n");
        scanf("%d",&n);
        result=recursion(n);                                                              C:\Users\Lenovo\Desktop\白玉\练习41.cpp        undefined reference to `recursion(int)'
        printf("%d!=%ld\n",n,result);                                                     C:\Users\Lenovo\AppData\Local\Temp\ccIUDdP6.o        In function `recursiong(int)':
}                                                                                         C:\Users\Lenovo\Desktop\白玉\练习41.cpp        undefined reference to `recursion(int)'
long recursiong(int n)                                                                    C:\Users\Lenovo\Desktop\白玉\collect2.exe        [Error] ld returned 1 exit status
{
        long temp_result;
        if(n<0)
        {
                printf("n<0,input error!\n");
        }
        else if(n==0||n==1)
        {
                temp_result=1;
        }
        else
        {
                temp_result=recursion(n-1)*n;
        }
        return temp_result;
}
如各位看到了，这段递归函数的相关程序，我是按照小甲鱼老师的例题照打的，可是一直编译不通过，右边的是程序显示出错误的地方，可是就是解决不了，按理说 recursion不是已经在头文件那里定义了吗？怎么程序还是会报错？

那你仔细检查一下单词是否拼写错了？多了个g