c-49 阶乘

5*  5*4*3*2*1=120

4*  4*3*2*1=24

n*  n*(n-1)*(n-2).....

#include <stdio.h>

int GetNum(int num)
{
 if (num == 1) return 1;
 return num*GetNum(num - 1);
}

int main(int argc, char* argv[])
{
 printf("%d ", GetNum(10));
 getchar();
 return 0;
}