请各位高手帮我编写个JAVA程序： 题目：编程计算sum=1-1/2!+1/3!-.....(-1)的n-1次方乘1/n!

Question

sum = 1 - 1/2! + 1/3! -......(-1)的n-1次方乘1/n!对此问题编程用JAVA
谢谢各位了

Answer 1

public class sum {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int n = 5;//n需要预先设定
int x = -1;
float sum = 0;
for(int i=1;i<=n;i++){
x = x*(-1);
float fac = 1;
for(int j=1;j<=i;j++){
fac = fac*j;
}
float k = 1/fac;
sum = sum+x*k;
}
System.out.println("sum="+sum);
}

}