要求编写一个java application,求出e=1+1/1!+1/2!+1/3!+...+1/n!+...的近似值,要求误差小于0.0001。

public class Test {
//求n的阶乘
public static int fn(int n){
if(n <= 1){
return 1;
}
return n*fn(n-1);
}

//求和
public static double sum(int n){
double sum = 0;
for(; n >= 1; n--){
sum = sum + (double)1/fn(n);//注意要强制转换成float或者double
}
return sum;
}

public static void main(String args[]){
int n = 10;
System.out.println(sum(n));
}
}