C++ Program to performed swap of two number without using third variable

C++ Program to performed swap of two number without using third variable #include<iostream.h> #include<conio.h> void main() {  int a,b;  clrscr();  cout<<"\nEnter First Number : ";  cin>>a;  cout<<"\nEnter Second Number : ";  cin>>b;  cout<<"\nBefore Swap";  cout<<"\nFirst Number = "<<a;  cout<<"\nSecond Number = "<<b;     a=a+b;  b=a-b;  a=a-b;  cout<<"\nAfter Swap";  cout<<"\nFirst Number = "<<a;  cout<<"\nSecond Number = "<<b;  getch(); }