c++的 求1/1！-1/2！+1/3！-1/4！……1/10！的和。用函数实现
#include <stdio.h>
double func(int n)
{
int p = 1;
for (int i = 2; i <= n; i++) p *= i;
if (n % 2 == 1)
return 1.0 / p;
else
return -1.0 / p;
}
int main()
{
double sum = 0;
for (int i = 1; i <= 10; i++)
sum += func(i);
printf("%lf\n", sum);
return 0;
}