Question

我正在处理一些代码。我陷入其中涉及Random nextInt（）方法的一部分。我遇到的问题是我的代码从数组的索引返回了完全相同的随机整数。我打算做的是遍历一个for循环，对于我的16个迭代中的每一个，我都希望Random的nextInt（）方法通过索引从数组中选择一个字符串并将其打印到屏幕上。目前，我能够从每个索引中生成1个随机字符串。在接下来的15次迭代中，我的代码将打印相同的随机选择，而不是随机选择一个新的随机选择。

import java.awt.Color;
import java.util.*;
import java.util.Random;

class Main {
    private int numStrings = 6; 
    private double guitarLength = 28.2;
    private String guitarManufacturer = "Gibson";
    private Color guitarColor = Color.RED; 
    private int musicLength = 16;
    private static int i = 1;
    private static Random rand = new Random();

public Main (){
    this.numStrings = numStrings; 
    this.guitarLength = guitarLength;
    this.guitarManufacturer = guitarManufacturer;
    this.guitarColor = guitarColor;
}

public Main (int strings, double length, String manufacturer, Color color){
     numStrings = strings;
     guitarLength = length;
     guitarManufacturer = manufacturer;
     guitarColor = color;
     System.out.printf("%d, %f, %s, %s", numStrings, guitarLength, guitarManufacturer, guitarColor + "\n");
}

public int getNumStrings() {
  return this.numStrings;
}

public double getGuitarLength() {
  return this.guitarLength;
}

public String getGuitarManufacturer() {
  return this.guitarManufacturer;
}

public Color getGuitarColor(){
  return this.guitarColor;
}

public static void playGuitar(){
    String[] musicNotes = {"A", "B", "C", "D", "E", "F", "G"};
    String[] musicDuration = {"(0.25)","(0.5)","(1)", "(2)","(4)"};
    int index1 = rand.nextInt(musicNotes.length);
    int index2 =  rand.nextInt(musicDuration.length);
     for (i = 1; i < 17; i++){
        System.out.print(musicNotes[index1]);
        System.out.print(musicDuration[index2] + ",");
        }
     }

public static void main (String args[] ){
    Main newGuitar = new Main(6, 24.75, "Les Paul", Color.white);
    playGuitar();
 }
}

Answer 1

您只生成两个随机数（index1和index2），然后在循环中多次使用它们。

您应该为循环的每次迭代生成新的随机数：

for (i = 1; i < 17; i++) {
    int index1 = rand.nextInt(musicNotes.length);
    int index2 =  rand.nextInt(musicDuration.length);
    System.out.print(musicNotes[index1]);
    System.out.print(musicDuration[index2] + ",");
}

Answer 2

您正在循环开始之前调用rand.nextInt，因此在整个循环中它们的值相同。您需要在循环内移动这两行。

Java-返回相同整数的随机nextInt方法

2 个答案: