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 = 1;
		for (i = 1; i <= j; i++)
		{
			ret = i * ret;
		}
		sum += ret;
	}
	printf("sum =%d\n", sum);
	return 0;
}