Question

Java入门：定义MyPoint类

定义MyPoint类（表示点），重载toString()方法。在TestMyPoint.java的main方法中实例化MyPoint类的对象start和end，并通过字符串连接运算输出如下格式：
start point is start[x,y]
end point is end[x,y]

Answer 1

MyPoint.java

public class MyPoint{
private double x;
private double y;

public MyPoint(){
this.x=0;
this.y=0;
}

public MyPoint(double x, double y){
this.x=x;
this.y=y;
}

public double getX(){
return this.x;
}

public double getY(){
return this.y;
}

public void setX(double x){
this.x=x;
}

public void setY(double y){
this.y=y;
}

public String toString(){
return "["+this.x+","+this.y+"]";
}
}

TestMyPoint.java
public class TestMyPoint{
public static void main(String[] args){
Point start=new Point();
Point end=new Point(2,3);
System.out.println("start point is start"+start.toString());
System.out.println("end point is end"+end.toString());
}
}

Answer 2

class MyPoint {
String name;
int x;
int y;
public MyPoint(String name,int x,int y){
this.name = name;
this.x = x;
this.y = y;
}
public String toString(){
return this.name+" point is "+this.name+"["+this.x+","+this.y+"]";
}
}
public class TestMyPoint{
public static void main(String[] args) {
MyPoint start = new MyPoint("start",1,2);
MyPoint end = new MyPoint("end",3,4);
System.out.println(start);
System.out.println(end);
}
}

Answer 3

public class TestMyPoint {
public static void main(String[] args){
Mypoint start=new Mypoint(3,4);
Mypoint end=new Mypoint(7,10);
System.out.println("start point is start"+start.toString());
System.out.print("end point is end"+end.toString());
}
}
class Mypoint {
int x;
int y;
Mypoint(int x,int y){
this.x=x;
this.y=y;
}
public String toString(){
return ("["+x+","+y+"]");
}
}