杭电 2011 ( 多项式求和 ) java

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
int num = sc.nextInt();
int k = 0;
while (k < num) {

double sum = 0;
double sum1 = 0;
int i = sc.nextInt();
for (int n = 1; n <= i; n++) {
if (n % 2 != 0) {
sum = sum + Math.pow(n, -1);

} else {

sum1 = sum1 - Math.pow(n, -1);
}

}

System.out.printf("%.2f",(sum + sum1));
System.out.println();
k++;
}
}
}
}