Swap function in java

[viral patel]

Can anyone show me how to write Swap funtion in java. I tried but its not working properly.COde will be help lot.

[David Weitzman]

If you're from a C++ background, you may be envisioning something like this:

int one = 1;
int two = 2;
swap(one, two);
System.out.println("one = " + one "; two = " + two);
// Prints "one = 2; two = 1"

Alas, you cannot have a method with precisely those semantics in Java.
You'll have to use a temporary variable to swap two variables.
If you'd like to swap two items in an array, you can just do what comes naturally:

void swap(int[] array, int i, int j) {
  int temp = array[i];
  array[i] = array[j];
  array[j] = temp;
}

[Michael Morris]

If you want to do it without a temporary holder check out this thread.

[Jeanne Boyarsky]

Just to elaborate on what David said:
You can't use a swap function with the semantics swap(int a, int b) because ints are passed by value, not by reference. If you want to swap the values of two objects, you can usually do that. You can also use the array as David explained.
If you are just using integers, it's less complicated to just do it in the code instead of in a separate function.

[F A H A D]

hi,
here goes buddy...

class swapping{
public static void swap(int num1, int num2){
num1=num1+num2;
num2=num1-num2;
num1=num1-num2;

System.out.println("After Swapping");
System.out.println("Value 1:: " + num1);
System.out.println("Value 2:: " + num2);
}
public static void main(String args[]){
int num1=2;
int num2=3;

System.out.println("Before Swapping");
System.out.println("Value 1:: " + num1);
System.out.println("Value 2:: " + num2);

swap(num1,num2);


}
}

[Spike Spiegel]

Hi,
I've been thinking about how to swap boolean values without using helper variables but I think it is impossible to do it in a clever way. The only way I could come up with is this:

 
    // code to swap 2 bools without temp variable(s)
    boolean bool1 = true ;
    boolean bool2 = false ;
    System.out.println( "--- BEFORE ---" ) ;
    System.out.println( "bool1 = " + bool1 ) ;
    System.out.println( "bool2 = " + bool2 ) ;
    // if they are the same there is no need to swap
    if ( bool1 == bool2 )
    {
    }
    
    else if ( ( bool1 == true ) && ( bool2 == false ) )
         {
           bool1 = false ;
           bool2 = true ;
         }
         else if ( ( bool1 == false ) && ( bool2 == true ) )
              {
                bool1 = true ;
                bool2 = false ;
              }
    System.out.println( "--- AFTER ---" ) ;
    System.out.println( "bool1 = " + bool1 ) ;
    System.out.println( "bool2 = " + bool2 ) ;

Regards,
Hans