java数组与枚举（课本练习）

Test.java

package yiyonng;

import excise.CopyArrayAndOverReading;
import excise.Overreading1;
import excise.Overreading2;
import excise.yinyong;
public class Test {
    public static void main(String[]args){
        System.out.println("/////the exceriseof 7._1/////");
        yinyong yin=new yinyong ();
        yin.showyinyong();
        //////////////////////////////////////////////
        System.out.println("/////the exceriseof 7_2/////");
        Overreading1 r1=new Overreading1();
        r1.showoverreading1();
        /////////////////////////////////////////////////
       
         System.out.println("/////the exceriseof 7_3(overreading)/////");
          Overreading2 r2=new Overreading2();
          r2.showoverreading2();
          
          /////////////////////////////////////////////////
       
         System.out.println("/////the exceriseof 7_4（arraycopy）/////"); 
         CopyArrayAndOverReading copy=new CopyArrayAndOverReading();
         copy.showarraycopy();
         
    }
    
}

CopyArrayAndOverReading.java

package excise;
import java.util.Arrays;
public class CopyArrayAndOverReading {
    public void showarraycopy(){
          int[] aa={1,2,3,4};
          int[] bb={100,200,300,400};
         System.arraycopy(aa,0,bb,0,aa.length);//复制length个元素
         System.out.println("the values of bb");
         System.out.println(Arrays.toString(bb));
    }

}

Overreading1.java

package excise;
public class Overreading1 {
     public void  showoverreading1(){
         int[] c={1,2,3,4};
        char[] d={'a','b','c','d'};
        for(int n=0;n

Overreading2 .java

package excise;
import java.util.Arrays;
public class Overreading2 {
    public void showoverreading2(){
         int []show1={1,2,3,4,5};
         System.out.println(Arrays.toString(show1));//遍历数组，注意上面还有声明
    }
}

yingyong.java

package excise;
public class yinyong {
     public  void showyinyong(){
      int[] a={1,2,3,4};
        int[] b={100,200,300};
        System.out.println("there are"+a.length+" elements of a");
        System.out.println("there are"+b.length+" elements of b");
        System.out.println("address of a="+a);
        System.out.println("address of b="+b);
        System.out.println("a==b is "+(a==b));
        a=b;
        System.out.println("there are "+a.length+" elements of a");
        System.out.println("there are "+b.length+" elements of b");
        System.out.println("a==b is "+(a==b));
        System.out.println("a[0]="+a[0]+",a[1]="+a[1]+",a[2]="+a[2]);
        System.out.println("b[0]="+b[0]+",b[1]="+b[1]+",b[2]="+a[2]);
        
    }
    
}

运行结果：