1.4双重循环实现阶乘相加1！+2！+.....+100!

int t,s=0;
	for (int i = 1; i <= 2; i++)
	{
		t = 1;
		for (int j = 1; j <= i; j++) {
			t = t * j;		
		}
		s += t;
	}
	cout << s << endl;