求n的阶乘 int main() { int i = 0; int n = 0; int ret = 1; scanf("%d", &n); for (i = 1; i <= n; i++) { ret = i * ret; } printf("ret =%d\n", ret); return 0; } 求1!+2!+3! int main() { int i = 0; int n = 0; int j = 0; int ret = 1; int sum = 0; for (j = 1; j <= 3; j++) { ret = ...