#include <iostream>
using namespace std;
int fac( int n )
{
int result = 1;
while( n > 1 )
{
result = result * n;
n = n - 1;
}
return result;
}
int BS(int n)
{ int i = 0;
if( n % 2 == 0 )
{
i = -1;
}
if( n % 2 == 1)
{
i = 1;
}
return i;
}
int main() {
int sum = 1;
int n = 0;
cout << "请输入一个正整数n,以求1-1/2!+1/3!-1/4!+...-1/n!的值:";
cin >> n;
while( n > 1 )
{
sum = sum + BS( n ) * ( 1 / fac( n ) );
n = n - 1 ;
}
cout << "1-1/2!+1/3!-1/4!+...-1/n!的值为:"<< sum << endl;
return 0;
}
不好意思 题目打错了!应该是:(1/1!-1/2!+1/3!-1/4!+…-1/n!)