从java数组中获取五个随机元素

Question

我已经在这个项目上工作了几天，我能够完成大部分工作，但我一直在努力从我的阵列中取出五个不同的项目。不过，我可以选择相同的项目五次。这是我的代码的样子：public class CardGuessingGame {    /**     * @param args the command line arguments     */    public static void main(String[] args) {        String[] myCards = new String[]{"two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "jack", "queen", "king", "ace"}; // Array for cards        Random rand = new Random(); //random construction        rand.nextInt(13); // Sets rand to 0-12 int        //int randomNums = rand.nextInt(13); // sets randNums from 0-12        int randomNums = rand.nextInt(myCards.length); //Randomizes "randomNums to the length of the array"        String cardInHand = myCards[(int)randomNums];        for (randomNums=0; randomNums < 5; randomNums++) {            System.out.println(cardInHand);        }        System.out.print("Guess the card in my hand: "); // Prints to user asking for guess        Scanner answer = new Scanner(System.in); // gets user input        String s = answer.nextLine(); //stores user input inside variable s        if(s.equals(cardInHand)) {            System.out.println("I do have that card in hand");        } else {            System.out.println("I do not have that card in hand!");        }        System.out.print("These were the cards I had in hand: ");        System.out.println(cardInHand);    }}这是输出run:fourfourfourfourfourGuess the card in my hand: fourI do have that card in handThese were the cards I had in hand: four我现在所拥有的有效，但不正确。

Answer 1

这是一个有效的代码，只需要独特的卡片。首先，您应该知道哪些变量是数组，哪些不是。

调用rand.nextInt(13);不会将 Random 实例设置为生成 1 到 13 之间的随机数，但实际上会生成一个。

你的随机数生成应该放在循环中。手中的卡片需要包含多个值，因此应使用数组。

import java.util.Arrays;

import java.util.Collections;

import java.util.LinkedList;

import java.util.List;

import java.util.Scanner;

public class CardGuessingGame {

    /**

     * @param args

     *            the command line arguments

     */

    public static void main(String[] args) {

        String[] myCards = new String[] { "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten",

                "jack", "queen", "king", "ace" }; // Array for cards

        //Random rand = new Random(); // random construction

        //rand.nextInt(13); // Sets rand to 0-12 int

        // int randomNums = rand.nextInt(13); // sets randNums from 0-12

        String[] cardsInHand = new String[5];

        List<String> cards = new LinkedList<>(Arrays.asList(myCards));

        Collections.shuffle(cards);

        for (int i = 0; i < 5; i++) {

            //This will not give you unique cards!

            //int randomNums = rand.nextInt(myCards.length); // Randomizes "randomNums to the length of the array"

            cardsInHand[i] = cards.remove(0);

        }

        System.out.println(Arrays.toString(cardsInHand));

        System.out.print("Guess the card in my hand: "); // Prints to user asking for guess

        Scanner answer = new Scanner(System.in); // gets user input

        String s = answer.nextLine(); // stores user input inside variable s

        //Some kind of contains method. You can traverse the array use a list or do however you like

        Arrays.sort(cardsInHand);

        if (Arrays.binarySearch(cardsInHand,s) >= 0) {

            System.out.println("I do have that card in hand");

        } else {

            System.out.println("I do not have that card in hand!");

        }

        //Close the stream

        answer.close();

        System.out.print("These were the cards I had in hand: ");

        System.out.println(Arrays.toString(cardsInHand));

    }

}