问题 1066: 2004年秋浙江省计算机等级考试二级C 编程题(2)

import java.util.Scanner;

public class Prog1066 {

public static void main(String[] args) throws Exception {

Scanner sc = new Scanner(System.in);

double x = sc.nextDouble();

double n = sc.nextDouble();

double sum = 0.0;

for (int i = 1; i <= n; i++) {

double sum1 = 1;

for (double j = 1; j <= i; j++) {

sum1 *= j;

}

sum += ((Math.pow(-1, i + 1)) * (Math.pow(x, i) / sum1));

}

String s = String.format("%.4f", sum);

System.out.println(s);

}

}