编写一个类，该类的方法可以接收一个整数N，计算并输出下列结果：

import java.io.*;
public class Test {
public static int jiecheng(int n)
{
if(n == 1)
{
return 1;
}
else
{
return n*jiecheng(n-1);
}

}
public static void main(String[] args) {
System.out.println("输入参数N");
int n = 0;
double sign = -1;
double result = 0;
try {
BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
n = Integer.parseInt(in.readLine());
} catch (Exception e) {}
for(int i = 1;i <= n;i++)
{
sign = (-1)*sign;
result = result + (sign/jiecheng(i));
System.out.println(sign/jiecheng(i));
}
System.out.println("结果："+result);
}
}

这个运行会快很多，用内存也会小很多

double compute(int n) {
double r = 1;
boolean positive = false;
int factorial = 1;
for(int i=2;i<=n;i++) {
factorial *= i;