equaltest1.java

java经典的源代码 我非常喜欢这个源代码 对于编程很有好处

class A{
  int a=1;
}

public class equalTest{
   public static void main(String[] args) {
    A obj1=new A();
    A obj2=new A();
    String s1,s2,s3="abc",s4="abc";
    s1=new String("abc");
    s2=new String("abc");
    System.out.println("s1=s2?"+(s1.equals(s2)));
    System.out.println("s1=s3?"+(s1==s3));
    System.out.println("s1=s3?"+(s1.equals(s3)));
    System.out.println("s3=s4?"+(s3==s4));
    System.out.println("s2=s3?"+(s2.equals(s3)));
    System.out.println("obj1=obj2?"+(obj1.equals(obj2)));
    System.out.println("s1=s2?"+(s1==s2));
    obj1=obj2;
    System.out.println("obj1=obj2 after obj1=obj2 ?"+(obj1.equals(obj2)));
    System.out.println("obj1=obj2 after obj1=obj2 ?"+(obj1==obj2));
  }
}
class A{
  int a=1;

  public boolean equals(Object obj){
    if(obj instanceof A){
      A temp=(A)obj;
      if(temp.a==this.a)
        return true;
      else
        return false;
    }
    return false;
  }
}

public class equalTest1{
   public static void main(String[] args) {
    A obj1=new A();
    A obj2=new A();
    String s1,s2,s3="abc",s4="abc";
    s1=new String("abc");
    s2=new String("abc");
    System.out.println("s1=s2?"+(s1.equals(s2)));
    System.out.println("s1=s3?"+(s1==s3));
    System.out.println("s1=s3?"+(s1.equals(s3)));
    System.out.println("s3=s4?"+(s3==s4));
    System.out.println("s2=s3?"+(s2.equals(s3)));
    System.out.println("obj1=obj2?"+(obj1.equals(obj2)));
    System.out.println("s1=s2?"+(s1==s2));
    obj1=obj2;
    System.out.println("obj1=obj2 after obj1=obj2 ?"+(obj1.equals(obj2)));
    System.out.println("obj1=obj2 after obj1=obj2 ?"+(obj1==obj2));
  }
}