java - 石头剪刀布问题——只有一半返回结果

Question

我是 Java 新手，任务是使用嵌套 if 语句编写两人石头/剪子布游戏。我的结果只有一半是打印结果

当我使用“else if ("rock".equals(player1) && "paper".equals(player2))”而不是嵌套的 if 语句时，该程序适用于所有组合，但嵌套的 if 是标题。

    Scanner in = new Scanner(System.in);

    System.out.print("Player 1, please choose rock, paper, or scissors: ");
    String player1 = in.next();         
    System.out.print("Player 2, please choose rock, paper, or scissors: ");
    String player2 = in.next(); 

    player1 = player1.toLowerCase();
    player2 = player2.toLowerCase();


    if (player1.equals(player2))
    {
        System.out.println("It's a tie!");
    }

    else if ("rock".equals(player1))    
    {
        if ("paper".equals(player2))
        {
            System.out.println("Paper covers rock - Player 2 wins!");
        }
    }

    else if ("rock".equals(player1))            
        {
        if ("scissors".equals(player2))     
        {
            System.out.println("Rock breaks scissors - Player 1 wins!");
        }
    }           

    else if ("paper".equals(player1))
    {
        if ("scissors".equals(player2))     
        {
            System.out.println("Scissors cut paper - Player 2 wins!");
        }
    }

    else if ("paper".equals(player1))
    {
        if ("rock".equals(player2))     
        {
            System.out.println("Paper covers rock - Player 1 wins!");
        }
    }       

    else if ("scissors".equals(player1))
    {
        if ("paper".equals(player2))        
        {
            System.out.println("Scissors cut paper - Player 1 wins!");
        }
    }
    else if ("scissors".equals(player1))
    {
        if ("rock".equals(player2))     
        {
            System.out.println("Rock breaks scissors - Player 2 wins!");
        }
    }

    else
    {
        System.out.println("Invalid input. Please try again using rock, paper, or scissors");
    }

    in.close();
    }

 }

我期望每种输入组合都有输出，但剪刀与石头、石头与剪刀、布与石头不会向控制台产生任何输出。

Answer 1

else if ("rock".equals(player1))    
{
    if ("paper".equals(player2))
    {
        System.out.println("Paper covers rock - Player 2 wins!");
    }
}
else if ("rock".equals(player1))            
    {
    if ("scissors".equals(player2))     
    {
        System.out.println("Rock breaks scissors - Player 1 wins!");
    }
}  

请注意，您有同一张支票两次。当第一个为 true 时，只有该 block 将执行，而下一个 else if... 将被跳过。要解决此问题，只需在一个 block 中对player2 进行所有检查即可:

else if ("rock".equals(player1))    
{
    if ("paper".equals(player2))
    {
        System.out.println("Paper covers rock - Player 2 wins!");
    }
    else if ("scissors".equals(player2))     
    {
        System.out.println("Rock breaks scissors - Player 1 wins!");
    }
}  

您还应该了解 switch 语句，它可以为问题提供替代解决方案。