Question

我对Java非常陌生，我正在制作这个程序，随机将机器人放入预定义的舞台。

当发生这种情况时，我正在主要测试我的addRobot方法

这是我的两个班级的代码：

import java.util.Scanner;
import java.util.Random;



public class RobotArena {

    private int xmax,ymax;
    Robot ro;
    RobotArena roaa;
    public static Robot rrr[];
    RobotArena (int xs, int ys, Random r){
        xmax = xs;
        ymax = ys;
        ro = new Robot(r.nextInt(xmax), r.nextInt(ymax), this); 
    }

    public void addRobot () {

    Scanner add = new Scanner(System.in); 
    System.out.print("How many robots would you like to add?");


    int numberofRobots = add.nextInt();
    rrr = new Robot[numberofRobots];
    add.close();

    for(int c=0 ;c < numberofRobots ; c++)
    {
        Random addro2 = new Random();
        int Xcoordinate = addro2.nextInt(xmax);
        int Ycoordinate = addro2.nextInt(ymax);
        rrr[c]= new Robot(Xcoordinate,Ycoordinate, null);
        System.out.println( rrr[c]);
    }

    }

import java.util.Random;

public class Robot {

    private int x, y, dx, dy, ID;
    private static int RobotID;
    private  RobotArena roA;


    Robot(){
        this(0,0, null);

    }

    Robot(int sx, int sy, RobotArena ra){
        x = sx;
        y = sy;
        dx = 1;
        dy = 1;
        roA = ra;
        ID = RobotID;
        RobotID++;


    }

    public String toString() {
        return "Robot ID = " + ID +", robot is at " + x + ", " + y;
    }

    public boolean isHere(int ix, int iy) {
            if (ix == x && iy == y) {
                return true;
            }
            else 
            {
                return false;
            }
    }


    public static void main(String[] args) {

        RobotArena rrr1;
        Random addro = new Random();
        rrr1 = new RobotArena(20, 5, addro);
        rrr1.addRobot();
        }

}

即使我从不调用toString函数，它为每个机器人的ID和竞技场中的位置生成一个字符串，

Answer 1

它间接称为。您调用directory$ = "/Users/directorypath" listfile$ = "test.txt" Read Strings from raw text file... 'directory$'/'listfile$' last = Get number of strings listfile2$ = listfile$ - ".txt" # loop through each file for a from 1 to last select Strings 'listfile2$' textgrid$ = Get string... 'a' Read from file... 'directory$'/'textgrid$' object_name$ = selected$("TextGrid") Read from file... 'directory$'/'object_name$'.wav # rearrange tiers select TextGrid 'object_name$' Duplicate tier: 3, 1, "MAU" Remove tier: 4 Insert interval tier: 1, "subphone" n = Get number of intervals: 3 for i to n @instance: "strikes" @instance: "raindrops" @instance: "and" @instance: "rainbow" @instance: "into" @instance: "round" @instance: "its" @instance: "its" endfor endfor procedure instance: .target_word$ label$ = Get label of interval: 3, i if label$ == .target_word$ index = i i += n # get the start and end point of the word startpoint = Get starting point... 3 index endpoint = Get end point... 3 index select TextGrid 'object_name$' plus Sound 'object_name$' View & Edit editor TextGrid 'object_name$' # annotation Select... startpoint endpoint Zoom to selection pause Annotate stops then continue Close endeditor endif endproc并实现该方法，以便打印给定参数的System.out.println(rrr[c]);。

让我们来看看recent implemention（ 8u40-b25 ）。 argument.toString()指向System.out类型的对象，这是PrintStream方法的实现方式：

println

它会调用public void println(Object x) { String s = String.valueOf(x); synchronized (this) { print(s); newLine(); } }（implementation）：

String.valueOf(x)

在论证上调用public static String valueOf(Object obj) { return (obj == null) ? "null" : obj.toString(); }。

Answer 2

这是因为在java中 - 如果你打印一个对象 - 将隐式调用toString方法

Answer 3

如果你这样做：

onExpandedRowsChange

然后println方法在内部为你调用toString ...这就是那个beh的真实解释。

调用我的toString函数而不调用它

3 个答案: