Introduction to Java Programming编程题5.13<数列求和>

/*
Enter a digit number: 3
i   m(i)
1   0.5
2   1.1666666666666665
3   1.9166666666666665
*/
import java.util.Scanner;

public class SumOrderedSeries {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);

    System.out.print("Enter a digit number: ");
    int number = input.nextInt();

    displaySumOrderedSeries(number);
  }

  public static void displaySumOrderedSeries(int n) {
    System.out.println("i\tm(i)");

    for (int i = 1; i <= n; i++)
      displaySumBody(i, sumOrderedSeries(i));
  }

  public static double sumOrderedSeries(int n) {
    double mi = 0;
    for (int i = 1; i <= n; i++) {
      mi += i / (i + 1.0);  //注意：此处必须为1.0，否则mi的结果将会舍弃小数点。
    }
    return mi;
  }

  public static void displaySumBody(int i, double mi) {
    System.out.println(i + "\t" + mi);
  }
}