//重写Point和Circle类的equals()、toString()方法，并测试这些方法的正确性。
class Point{
int x,y;
Point(){
x=0;y=0;
}
Point(int xx,int yy){
this.x=xx;
this.y=yy;
}
int getX(){
return x;
}
int getY(){
return y;
}
public boolean equals(Object obj){
Point p=(Point)obj;
if(x==p.x&&y==p.y)
return true;
else
return false;
}
public String toString(){
return ("点的横坐标:"+x+",点的纵坐标:"+y)；
}
double distance(Point p)
{
return Math.sqrt((x-p.x)*(x-p.x)+(y-p.y)*(y-p.y));
}
}
class sun{
public static void main(String args[]){
double d;
boolean a;
char b,c;
Point myPoint=new Point(1,1);
Point point1=new Point(1,2);
d=myPoint.distance(point1);
a=myPoint.equals(point1);
b=myPoint.toString();
c=point1.toString();
System.out.println("两点之间距离为："+d);
System.out.println("两个点是否相等："+a);
System.out.println("第一个点参数："+b);
System.out.println("第二个点参数："+c);
}
}
我不会调用toString方法，想请教高手这么调用对吗，要是该应该怎么改，谢谢！
------解决方案--------------------------------------------------------
用刚刚那个帖子的代码给你贴个例子
- Java code
class Point{ //点类的定义 private int x; private int y; public Point(){ x=0; y=0; } @Override public String toString() { return "Point{" + "x=" + x + ", y=" + y + '}'; } public Point(int xx,int yy){ this.x=xx; //this不加也可运行 this.y=yy; } public int getX(){ //后面用到了 return x; } public int getY(){ return y; } public double distance(Point p){ //对象小写，类大写 return Math.sqrt((x-p.x)*(x-p.x)+(y-p.y)*(y-p.y)); //用来求两点之间距离 } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof Point)) return false; Point point = (Point) o; if (x != point.x) return false; if (y != point.y) return false; return true; } @Override public int hashCode() { int result = x; result = 31 * result + y; return result; }}class Circle{ //圆类的定义 private int radius=0; //int x,y; //Point类型 圆心跟着Point走 不用再次定义x,y private Point center; //定义点类的圆心 public Circle(){ radius=1; //圆类的构造函数 center=new Point(); //申请空间 } @Override public String toString() { return "Circle{" + "radius=" + radius + ", center=" + center + '}'; } public Circle(int xx,int yy,int r){ radius=r; center=new Point(xx,yy); //因为没有定义Circle中的x，y；所以直接引用Point的构造函数即可 } public Circle(Point c,int r){ radius=r; center=c; } public double perimeter(){ return 2*3.14*radius; //以刚开始声明的radius为准 } public double area(){ return 3.14*radius*radius; } public int relation(Circle c){ int cx = c.center.getX(); //得到圆的圆心的横坐标 int cy = c.center.getY(); int cr = c.radius; int tx = this.center.getX(); int ty = this.center.getY(); Point myPoint=new Point(tx,ty); Point point1=new Point(cx,cy); double distance1 = myPoint.distance(point1); //定义圆心距，圆心与圆心之间的距离,的通过对象调用distance； //distance1圆心距 //第一个圆半径radius //第二个圆半径cr if(distance1 > (cr+radius)){ return 0;//相离 }else if(distance1 ==(cr+radius)){ return 1;//外切 }else if(distance1 < (cr+radius)&&distance1>Math.abs(cr-radius)){ return 2;//相交 }else if(distance1==Math.abs(cr-radius)){ return 3;//内切 }else if(distance1<Math.abs(cr-radius)){ return 4;//包含 }else{ return -1; } } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof Circle)) return false; Circle circle = (Circle) o; if (radius != circle.radius) return false; if (!center.equals(circle.center)) return false; return true; } @Override public int hashCode() { int result = radius; result = 31 * result + center.hashCode(); return result; }}public class Sun{ public static void main(String[] args){ double a,b,flag; Circle circle1=new Circle(12,12,4); //用来预备着求圆的位置关系的 Circle circle2=new Circle(3,12,5); Circle circle3=new Circle(3,12,5); System.out.println("cricel1:"+circle1); System.out.println("circle1 equals(circle2) result:"+circle1.equals(circle2)); System.out.println("circle3 equals(circle2) result:"+circle3.equals(circle2));// a=circle1.perimeter(); //上面改成无参的了// b=circle1.area();// flag=circle1.relation(circle2);// if(flag==0)// System.out.println("两个圆的关系是：两个圆为相离");// if(flag==1)// System.out.println("两个圆的关系是：两个圆为外切");// if(flag==2)// System.out.println("两个圆的关系是：两个圆为相交");// if(flag==3)// System.out.println("两个圆的关系是：两个圆为内切");// if(flag==4)// System.out.println("两个圆的关系是：两个圆为包含");// if(flag==-1)// System.out.println("两个圆的关系是：未知");// System.out.println("圆的周长是："+a);// System.out.println("圆的面积是："+b); }}