第六章第三十七題（格式化整數）(Format an integer) - 編程練習題答案

6.37（格式化整數）使用下麵的方法頭編寫一個方法，用於將整數格式化為指定寬度：

public static String format(int number, int width)

方法為數字number返回一個帶有一個或多個以0作為首碼的字元串。字元串的位數就是寬度。比如，format(34,4)返回0034，format(34,5)返回00034。如果數字寬於指定寬度，方法返回該數字的字元串表示。比如，format(34,1)返回34。

6.37(Format an integer)Write a method with the following header to format the integer with the specified width.

public static String format(int number, int width)

The method returns a string for the number with one or more prefix 0s. The size of the string is the width. For example, format(34, 4) returns 0034 and format(34, 5) returns 00034. If the number is longer than the width, the method returns the string representation for the number. For example, format(34, 1) returns 34.
Write a test program that prompts the user to enter a number and its width, and displays a string returned by invoking format(number, width).

下麵是參考答案代碼:

// https://cn.fankuiba.com
import java.util.Scanner;

public class Ans6_37_page205 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int number = input.nextInt();
        System.out.print("Enter the number width: ");
        int width = input.nextInt();
        System.out.println(format(number,width));
    }
    public static String format(int number, int width) {
        String format = "";
        int numberLenth = (number+"").length();
        if (numberLenth < width) {
            for (int i = 1; i <=width-numberLenth; i++)
                format = format + "0";
            return format+number;
        }
        else
            return ""+number;// String strNumber = String.valueOf(number)
    }
}

適用Java語言程式設計與數據結構（基礎篇）（原書第11版）Java語言程式設計（基礎篇）（原書第10/11版）更多