[Java, JS]-do not use the third variable to exchange two integers

Source: http://www.javaeye.com/topic/645596

 

If you do not use the third variable to exchange two integers, you may have encountered this question. For example:

JavaCode

 Public     Class  Person {

  Public     Static     Void  Main (string [] ARGs ){
  //  Use addition and subtraction  
   Int  A  =     10  , B  =     5  ;
A  =  A  +  B;
B  =  A  - B;
A  =  A  -  B;

System. Out. println (  "  A =  "     +  A  +     "  \ NB =  "     + B );
}
} 

 

There is another method that is more efficient:

Java code

  Public     Class  Person {

  Public     Static     Void  Main (string [] ARGs ){
  // The exchange rate is met by using a number-exclusive or equal to 0 and exclusive operations.  
    Int  A  =     10  , B  =     5  ;
A  =  A  ^  B;
B =  A  ^  B;
A  =  A  ^  B;

System. Out. println (  "  A =  "     +  A  +     " \ NB =  "     +  B );
}
} 

 

 

Of course, the above two typesAlgorithmThe corresponding js also supports the following:

JS Code

  VaR  A  =     11  , B  =    22  ;
A  =  A  +  B;
B  =  A  -  B;
A  =  A  -  B;

Console. Log (  +  '  \ N '  +  B) 

Or

JS Code

  VaR  A  =     11  , B  =     22  ;
A  =  A ^  B;
B  =  A  ^  B;
A  =  A  ^  B;

Console. Log (  +  '  \ N  '  +  B) 

 

 

 

However, if two variables are of the object type, Java (strong type) seems powerless. But JS works. There are still many implementation methods, such:

JS Code

  VaR  A  =  {Name:  '  Jack  '  }, B  =  {Name:  '  Tom  ' };
A  =  [A, B];
B  =  A [  0  ];
A  =  A [  1  ];

Console. Log (A. Name  +  '  \ N  '  +  B. Name) 

Or

JS Code

  VaR  A  =  {Name:  '  Jack  '  }, B  =  {Name:  '  Tom  '  };
A  = {A: A, B: B };
B  =  A.;
A  =  A. B;

Console. Log (A. Name  +  '  \ N  '  +  B. Name) 

 

 

It is precisely the use of JS dynamic (weak type) systems and direct object/array features. Other strong types are not allowed. The compiler will prompt a type conversion error.

Http://en.wikipedia.org/wiki/XOR_swap Resources