//c++ program to swap two numbers without using a third number
#include 
#include 

int main()
{
      int a,b;
      clrscr();
      cout<<"Program to swap two numbers\nEnter first number:";
      cin>>a;
      cout<<"\nEnter second number:";
      cin>>b;
      a=a+b;
      b=a-b;
      a=a-b;
      cout<<"After swap\nFirst number: "<
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