【水题看法】连续阶乘之和

#include<stdio.h>
int main()
{
	float s = 0,t = 1;	
	int n;
	for(n = 1;n <= 20; ++n)
	{
		t = t * n; //n! = n * (n-1)! 
		s = s + t;
	}
	printf("1!+2!+3!+¡­¡­+20!=%e\n",s);
}

不需要分别计算 1! 2! 3! ……n!再相加