如图
#include <stdio.h>
void main() {
int fac(int num);
int n = 1;
int num;
for (num = 0; num <= 20; ++num) {
printf("%d! = %d\n", num, fac(num));
}
}
int fac(int num) {
register int n = 1, i; //寄存器变量
for (i = 1; i < num; i++) {
n = n * i;
}
return n;
}