java - 如何打印出正确的输出？

Question

CS101：实验 #12 写作课 II

在本实验中，您将编写三个类：Die、PairOfDice 和 Player。

Die 类模仿骰子的滚动。具体来说，这个类将实现以下方法：

 将骰子的面数初始化为 6 的默认构造函数。

 具有整数边数的重载构造函数（假设大于 1）。

 roll 生成并返回一个介于 1 和边数（含）之间的随机数。

 一种读取骰子面值的访问器方法。

 返回面值的字符串表示形式的 toString 方法。

最大边数应作为私有常量存储在 Die 类中。还使用 Random 类作为随机数生成器。

PairOfDice 类模拟两个骰子的滚动。具体来说，这个类将实现以下方法：

 一个默认构造函数，它创建并将每个骰子的面数初始化为 6。

 一个重载的构造函数，它创建并采用两个整数边，每个骰子一个。

 roll 掷骰子并返回总和。

 读取骰子总和的访问器方法。

Player 类实现了 main 方法，该方法创建骰子对并将它们滚动数次以报告结果。

public class Player {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        
        Die die1 = new Die ();
        System.out.println ( die1);

        PairOfDice sum = new PairOfDice ( ); 
        System.out.println (sum );
        
}
}

import java.util.Random;

public class PairOfDice 
{
        private int maxSides = 6;
        private int sides = 1;
        private int maxSides2 = 6;
        private int sides2 = 1;
        private Random randNum;
        private Random randNum2;
        private int sum;
        public int die1;
        public int die2;
        
        
        public int MaxSides ()
        {
            maxSides = 6;
            maxSides2 = 6;
            return maxSides + maxSides2;

        }
        public PairOfDice (int roll)
        {
            randNum.nextInt (); 
            randNum2.nextInt ();
        }
        public int roll ()
        {   
            sides = randNum.nextInt ( maxSides) + 1; 
            sides2 = randNum2.nextInt ( maxSides2) + 1; 
              
            return  ((randNum.nextInt (maxSides) + 1) + ( randNum2.nextInt (maxSides2) + 1))  ; 

        }
        
        public int getfaceOfDie ( )
        {
            sum = sides + sides2;
            return sum;

        }

        public  String toString ()
        {
            return ( "Sum is:" + sum);
        }
    }

import java.util.Random;

public class Die 
{
    private int maxSides = 6;
    public int sides = 1;
    private Random randNum;


    // A default constructor initializing the number of sides of a die to 6.
    public int MaxSides ()
    {
        maxSides = 6;
        return maxSides;

    }

    // An overloaded constructor that takes an integer number of sides (assume greater than 1).
    public Die(int roll)
    {
        randNum.nextInt (6); 

    }


    //roll which generates and returns a random number between 1 and the number of sides

    public int roll ()
    {   
        sides = randNum.nextInt ( maxSides) + 1; 

        return  randNum.nextInt (maxSides) + 1; 

    }
    //An accessor method to read the value of the face on the die.
    public int getfaceOfDie()
    {
        return sides;

    }
    // A toString method returning the string representation of the face value.

    public  String toString ()
    {
        return ( "Die rolled:" + sides);
    }
}

我无法打印出来。这就是我得到的 _JAVA_OPTIONS：-Xmx512m 线程“main”中的异常 java.lang.Error：未解决的编译问题：构造函数 PairOfDice() 未定义 语法错误，插入“VariableDeclarators”以完成 LocalVariableDeclaration roll 无法解决或是不是字段构造函数 Die() 未定义

at Player.main(Player.java:12)

在此处输入代码 import java.util.Random;

public class Die 
{
private int maxSides = 6;
public int sides = 1;
private Random randNum;


// A default constructor initializing the number of sides of a die to 6.
public int MaxSides ()
{
    maxSides = 6;
    return maxSides;

}

// An overloaded constructor that takes an integer number of sides (assume 
greater than 1).
public Die(int roll)
{
    randNum.nextInt (6); 

}


//roll which generates and returns a random number between 1 and the 
 number of sides

public int roll ()
{   
    sides = randNum.nextInt ( maxSides) + 1; 

    return  randNum.nextInt (maxSides) + 1; 

}
//An accessor method to read the value of the face on the die.
public int getfaceOfDie()
{
    return sides;

}
// A toString method returning the string representation of the face value.

public  String toString ()
{
    return ( "Die rolled:" + sides);
 }
}

import java.util.Random;

public class PairOfDice 
{
    private int maxSides = 6;
    private int sides = 1;
    private int maxSides2 = 6;
    private int sides2 = 1;
    private Random randNum;
    private Random randNum2;
    private int sum;
    public int die1;
    public int die2;
    
    
    public int MaxSides ()
    {
        maxSides = 6;
        maxSides2 = 6;
        return maxSides + maxSides2;

    }
    public PairOfDice (int roll)
    {
        randNum.nextInt (); 
        randNum2.nextInt ();
    }
    public int roll ()
    {   
        sides = randNum.nextInt ( maxSides) + 1; 
        sides2 = randNum2.nextInt ( maxSides2) + 1; 
          
        return  ((randNum.nextInt (maxSides) + 1) + ( randNum2.nextInt 
 (maxSides2) + 1))  ; 

    }
    
    public int getfaceOfDie ( )
    {
        sum = sides + sides2;
        return sum;

    }

    public  String toString ()
    {
        return ( "Sum is:" + sum);
    }
}

标签： javaloops

Answer 1

只需替换System.out.println(" ")为System.out.print(" ")：

public static void foo(int rows) {
    for (int i = 1; i <= rows; i++) {
        if (i > 1)
            System.out.print(' ');

        for (int j = 0; j < i; j++)
            System.out.print('X');
    }

    System.out.println();
}