java - 两个缺失的返回声明

Question

import java.util.Scanner;

public class BlackJack {

static Scanner stdin = new Scanner(System.in);
static String[] deck = new String[52];
static String dealerCard = "", dealerHiddenCard = "", userCard = "", userCardTwo = "";
static int dealerCounter = 0, userCounter = 0;

public static void main (String[] args) {




    System.out.println("\n***Welcome to the grand Command Line Casino!***" +
         "\n***Today we are only playing single deck Black Jack!***" +
         "\n***But that's what we do everyday! HAHA!***\n");

    //Creates Deck of cards
    String[] suit = { "Clubs", "Diamonds", "Hearts", "Spades" };
    String[] rank = { "2", "3", "4", "5", "6", "7", "8", "9", "10",
            "Jack", "Queen", "King", "Ace" };

    for (int a=0; a < rank.length; a++) {
        for (int b=0; b < suit.length; b++){
            deck[suit.length*a + b] = (rank[a] +" of "+ suit[b]);
        }
    }

    //Assigns two cards to the dealer 
    //Finds the Integer value of each card and adds it to the dealerCounter

    //first dealer card
    System.out.println("----Dealer's Cards:----");
    System.out.println("(Dealer's First Card Placed Face Down)");
    dealerHiddenCard = randomCard(dealerHiddenCard);
    dealerCard = assignValue(dealerHiddenCard);
    dealerCounter = Integer.parseInt(dealerCard);

    //second dealer card
    dealerCard = randomCard(dealerCard);
    System.out.println(dealerCard);
    dealerCard = assignValue(dealerCard);
    dealerCounter += Integer.parseInt(dealerCard);


    //Assigns two cards to the user 
    //Finds the Integer value of each card and adds it to the userCounter

    //first user card
    System.out.println("\n----Your Cards:----");
    userCardTwo = randomCard(userCardTwo);
    System.out.println(userCardTwo);
    userCardTwo = assignValue(userCardTwo);
    userCounter = Integer.parseInt(userCardTwo);

    //second user card
    userCard = randomCard(userCard);
    System.out.println(userCard);
    userCard = assignValue(userCard);
    userCounter += Integer.parseInt(userCard);

/////// HERES ONE /////////
/////// HERES ONE /////////
    userAceHandler(userCounter);
/////// HERES ONE /////////
/////// HERES ONE /////////

        if (userCounter == 21)                {
            System.out.println("Black Jack! You Win!"); }


    hitStay();

    dealersTurn();          
}



public static String randomCard(String draw) {
//Pulls a random card from the deck

    while (true) {
        //Generates a random number between 0 and 52
        int card = (int)(Math.random()*52);
        draw = deck[card];

        //Makes sure the same card isn't drawn twice
        if (draw == "0") {
            continue;}
        else {
            deck[card] = "0";
            return draw;}
    }

}



public static String assignValue(String cardName) {
//Assigns a number value to the card

    if (cardName.contains("2"))    {
        cardName = "2";         }
    if (cardName.contains("3"))    {
        cardName = "3";         }
    if (cardName.contains("4"))    {
        cardName = "4";         }
    if (cardName.contains("5"))    {
        cardName = "5";         }
    if (cardName.contains("6"))    {
        cardName = "6";         }
    if (cardName.contains("7"))    {
        cardName = "7";         }
    if (cardName.contains("8"))    {
        cardName = "8";         }
    if (cardName.contains("9"))    {
        cardName = "9";         }
    if (cardName.contains("10"))   {
        cardName = "10";        }
    if (cardName.contains("Jack")) {
        cardName = "10";        }
    if (cardName.contains("Queen")){
        cardName = "10";        }
    if (cardName.contains("King")) {
        cardName = "10";        }
    if (cardName.contains("Ace"))  {
        cardName = "11";        }

    return cardName;
}



public static void hitStay() {
//Processes a user 'Hit or Stay' selection

    int userInput;

    System.out.println("\nHit or Stay?");
    System.out.println("(1) Hit\n(2) Stay");
    userInput = stdin.nextInt();

    if (userInput == 1){    
    //Draws another card and adds it to the userCounter
    //Decides where to go depending on new userCounter value

        userCard = randomCard(userCard);
        System.out.println("\n"+userCard);
        userCard = assignValue(userCard);
        userCounter += Integer.parseInt(userCard);

/////// HERES ONE /////////
/////// HERES ONE /////////
        userAceHandler(userCounter);
/////// HERES ONE /////////
/////// HERES ONE /////////

        System.out.print("(Current Count = "+userCounter+")");

        if (userCounter == 21)                              {
            System.out.println("\n21! Now it's the dealer's turn");  
                                         }
        if (userCounter < 21)                       {
            hitStay();                   }

        if (userCounter > 21)                       {
            System.out.println("Bust! Maybe next time");
            System.exit(1);                  }
    }   
    if (userInput == 2){                       
        System.out.println("\nAlright, dealer's turn");
        System.out.println("\n(Dealer Flips His Hidden Card Over)");
        System.out.println(dealerHiddenCard);
        System.out.println("Dealer Count = "+dealerCounter+")");    
    }

}



public static void dealersTurn() {
//processes the dealers turn after the user has decided to 'stay'

    /////// HERES ONE /////////
    /////// HERES ONE /////////
    dealerAceHandler(dealerCounter);
    /////// HERES ONE /////////
    /////// HERES ONE /////////

    if (dealerCounter > userCounter)                {
        System.out.println("\nDealer Wins! Maybe next time.");   }
        System.exit(1);

    if (dealerCounter == userCounter && dealerCounter > 17)     {
        System.out.println("\nPush! (tie game)");
        System.exit(1);                      }

    if (dealerCounter > userCounter && dealerCounter < 21 
                    && dealerCounter >= 17)     {
        System.out.println("\nDealer Wins! Maybe next time.");
        System.exit(1);                      }

    if (dealerCounter < userCounter && dealerCounter >= 17)     {
        System.out.println("\nYou Win!");
        System.exit(1);                      }

    if (dealerCounter > 21)                     {
        System.out.println("\nDealer Bust! You Win!");
        System.exit(1);                      }

    if (dealerCounter == 21)                    {
        System.out.println("\nDealer Wins! Maybe next time.");
        System.exit(1);                      }

    if (dealerCounter < userCounter || dealerCounter < 17)      {
        dealerCard = randomCard(dealerCard);
        System.out.println("\n"+dealerCard);
        dealerCard = assignValue(dealerCard);
        dealerCounter += Integer.parseInt(dealerCard);
        System.out.println("(Dealer Count = "+dealerCounter+")");

        dealersTurn();                       }
}



public static int userAceHandler(int userCounter) {
//handles the situation if an Ace is drawn for the user

    if (userCounter >= 22 && userCard == "11")          {
        userCounter = userCounter - 10; 
        return userCounter;                  }
}



public static int dealerAceHandler(int dealerCounter) {
//handles the situation if an Ace is drawn for the dealer

    if (dealerCounter >= 22 && dealerCard == "11")          {
        dealerCounter = dealerCounter - 10;
        return dealerCounter;                    }


}

好的!我今天花了大约 10 个小时来制作这个游戏(这是一个基本的二十一点游戏)，在添加代码底部的最后两个方法之前，我让它运行得很好。他们将处理我代码中的“Ace”条件……不幸的是，当我尝试编译时，它告诉我我缺少两者的返回语句。我的编程生涯只有 5 周，而我的“制作我自己的方法”的职业生涯只有一周，所以我没有任何线索。我认为我做对了。

我会在我调用方法的地方用大量注释进行标记(每个方法总共只有 3 个点)

就像我说的，尽管在我添加这些之前它可以与其他所有东西完美配合。

非常感谢您的帮助!

Answer 1

您确实在userAceHandler 函数中有return 语句，但这还不够。如果 if 条件不为真怎么办？在这种情况下没有 return 语句。 Java 要求您为非 void 函数的每个 可能的代码路径提供一个return 语句。