带有 getter 的 if 语句的问题

Question

我的任务是开发一个应用程序来测试我的机器人 class。测试应用程序将询问用户机器人名称。然后它将使用该名称实例化一个 Robot 对象。然后应用程序将使用循环要求用户输入移动方向（x 或 y）和距离。当用户输入方向 q（退出）时，循环将终止。循环完成后，程序将显示机器人的最终位置和总行进距离。

我的主要问题是尝试使用我的机器人 class 并在涉及我的 if 语句时在我的 Prog3 class 中测试它。这是我的机器人 class:

public class Robot {
private String name;
private int xPosition;
private int yPosition;
private int totalDistance;

public Robot(String name, int xPosition, int yPosition, int totalDistance){
    super();
    this.name = name;
    this.xPosition = 0;
    this.yPosition = 0;
    this.totalDistance = totalDistance;
}

public String getName() {
    return name;
}

public int getxPosition() {
    return xPosition;
}

public int getyPosition() {
    return yPosition;
}

public int getTotalDistance() {
    return totalDistance;
}

public void moveX(int distance){
    xPosition += distance;
    totalDistance += Math.abs(distance);
}

public void moveY(int distance){
    yPosition += distance;
    totalDistance += Math.abs(distance);
}



}

现在这是我的 Prog3 class:

import java.util.Scanner;
public class Prog3 {

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    Robot robot = new Robot();

    //asks the user for robots name
    System.out.print("Enter robots name; ");
    Robot.name = in.nextLine();

    //asks the user to move the robot
    System.out.print("Direction of move (x/y/q): ");
    String move = in.nextLine();

    if( move.equals("x") ){
        System.out.print("Distance: ");

    }
    else if( move.equals("y") ){
        System.out.print("Distance: ");

    }
    else{


    }

}
}

如您所见，我的 Prog3 class 还没有完成，因为我完全卡住了。非常感谢您的宝贵时间。

Answer 1

"The loop will terminate when the user enters a direction of q (for quit)."。您的程序没有循环：

 Scanner in = new Scanner(System.in);
Robot robot = new Robot();

//asks the user for robots name
System.out.print("Enter robots name; ");
Robot.name = in.nextLine();

//asks the user to move the robot
System.out.print("Direction of move (x/y/q): ");
String move = in.nextLine();

if( move.equals("x") ){
    System.out.print("Distance: ");

}
else if( move.equals("y") ){
    System.out.print("Distance: ");

}
else{


}

这个代码段只会运行一次...如果你想让它循环你需要一个实际的

 While(<Conditional>) { 
// your code here
// a break point to exit the loop ( in your case "q" as the input string )
} // end while...

另外我有点困惑，因为你问题的措辞有点含糊。您的问题的性质究竟是什么？

Answer 2

您的构造函数没有意义，如果 x 和 y 值始终设置为 0，您为什么需要输入这些值？

我给你写了一个新的空白构造函数，并添加了一些 setter 方法

public class Robot {
private String name;
private int xPosition;
private int yPosition;
private int totalDistance;

public Robot(){
    name = null;
    xPosition = 0;
    yPosition = 0;
    totalDistance = 0;
}

public Robot(String name, int xPosition, int yPosition, int totalDistance){
    super();
    this.name = name;
    this.xPosition = 0;
    this.yPosition = 0;
    this.totalDistance = totalDistance;
}

public String getName() {
    return name;
}

public void setName( String name){
    this.name = name;
}

public int getxPosition() {
    return xPosition;
}

public void setxPosition(int x) {
    xPosition = x;
}

public int getyPosition() {
    return yPosition;
}

public void setyPosition(int y){
    yPosition = y;
}

public int getTotalDistance() {
    return totalDistance;
}


public void moveX(int distance){
    xPosition += distance;
    totalDistance += Math.abs(distance);
}

public void moveY(int distance){
    yPosition += distance;
    totalDistance += Math.abs(distance);
}

然后你需要在你的 main class

中对所有这些做一些事情

import java.util.Scanner;
public class Prog3 {

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    Robot robo = new Robot();

    //asks the user for robots name
    System.out.print("Enter robots name: ");
    String myName = in.next();
    robo.setName(myName);


    while( true ){
    //asks the user to move the robot
    System.out.print("Direction of move (x/y/q): ");
    String direction = in.next();
    if(direction.equals("q"))
        break;

    System.out.println("Distance of move: ");
    int distance = in.nextInt();


    if (direction.equals("x")) {
        robo.moveX(distance);
        System.out.println("moved" + distance +"units along the x axis");
    }
    else if (direction.equals("y")) {
        robo.moveY(distance);
        System.out.println("moved " + distance +" units along the y axis");
    }
    else {
        System.out.println("error");
    }
    }

    System.out.println("moved " + robo.getTotalDistance() + " total distance");

}
}

如果您还有其他问题，请告诉我。

带有 getter 的 if 语句的问题

Issue with if-statement with getters

java

eclipse

if-statement

getter-setter