20200721 千锤百炼软工人第十六天

今天完成了一个小程序

是一个圆类

其中感受到了java程序中析构函数，构造函数等等一系列的差别

在此附上代码和运行截图

package a20200720;

public class Circle {
 public static double PI=3.1415;
 private double radius;
 Circle(double a){
  this.radius=a;
  System.out.print("Constructor run");
 }
 Circle(){
  this.radius=0;
  System.out.print("Constructor run");
 }
 public void finalize() {
  System.out.print("Destructor run");
 }
 Circle(Circle a){
  this.radius=a.radius;
  System.out.print("CopyConstructor run");
 }
 public void setRadius(double r) {
  this.radius=r;
 }
 public double getRadius() {
  return radius;
 }
 public double circumference() {
  return PI*2*radius;
 }
 public double area() {
  return PI*radius*radius;
 }
 double fCircle_L(Circle r) {
  return PI*2*r.radius;
 }
 double fCircle_S(Circle r) {
  return PI*r.radius*r.radius;
 }
}

 

 

package a20200720;
import a20200720.Circle;
import java.util.Scanner;
public class Circlemain {
 public static void main(String[] arg) {
  Scanner r=new Scanner(System.in);
  double a=r.nextDouble();
  Circle c1=new Circle(a);
  System.out.print(" ");
  c1.setRadius(a);
  System.out.print(c1.circumference()+" ");
  System.out.print(c1.area()+" ");
  Circle c2=new Circle(c1);
  System.out.print(" ");
  System.out.print(c2.fCircle_L(c2)+" ");
  System.out.print(c2.fCircle_S(c2)+" ");
  c1=c2=null;
  System.gc();
 }
}