Introduction To Programming

Why programs ? Programming is nothing but making the computers think the same way a human thinks. Programs are made for obtaining a specific solution which can even be solved by humans which when solved by us may consume time..

Tuesday, December 8, 2009

Swapping without third variable

Swapping is interchanging the variable values.
For eg: if a=4 and b=5
after swapping a=5 and b=4. This swapping is done by a temporary variable. Now we're going to swap the values without using a temporary variable. Here's the program


#include < iostream.h >
void main()
{
int a=4, b=5;
a=a+b;
b=a-b;
a=a-b;
cout < < a < < b;
}

How it works?


first a=4 b=5
then a=a+b
now a will become 9.
then b=a-b will execute b=9-4=5
then a=a-b=9-5=4
that's all number swapped
NOTE:
you can do this operation by multiplication&division,x-or operators instead of using addition operators. i.e.,
a=a*b;
b=a/b;
a=a/b;
otherwise using x-or operators
a=a^b;
b=a^b;
a=a^b;