写了一个程序,计算50以内的阶乘:
#include <stdlib.h>
#define N 100
int main(int argc, char **argv)
{
int n;
int i, j, m, b;
int a[N] = {1};
if (2 != argc) {
printf("input error!\n");
printf("should be: exefile num\n");
exit(3);
}
n = atoi(argv[1]);
if (n > 50) {
printf("n should be not larger than 50\n");
exit(4);
}
b = 0;
for (i = 2; i <= n; i++) {
for (j = 0; j < N; j++) {
m = a[j] * i + b;
a[j] = m % 10;
b = m / 10;
}
}
for (i = N - 1; i >= 0; i --)
if (0 != a[i])
break;
printf("%d!=", n);
for (j = i; j >= 0; j--)
printf("%d", a[j]);
printf("\n");
return 0;
}
参考了下面的link: