Write a program to swap two variables using function.(call by value & call by reference).

 Practical 7

Call By value:

#include<iostream.h>
void swap(int x, int y);

int main ()
{
   int a  100;
   int b = 200;

   cout << "Before swap, value of a :" << a << endl;
   cout << "Before swap, value of b :" << b << endl;

   swap(a, b);

   cout << "After swap, value of a :" << a << endl;
   cout << "After swap, value of b :" << b << endl;

   return 0;
}
void swap(int x, int y)
{
   int temp;

   temp = x;
   x = y;
   y = temp;

   return;
}



output:


Before swap, value of a :100
Before swap, value of b : 200


After swap, value of a :100
After swap, value of b : 200

---

Call by Reference:

#include<iostream.h>
void swap(int &x, int &y);
int main ()
{
   int a = 100;
   int b = 200;

   cout << "Before swap, value of a :" << a << endl;
   cout << "Before swap, value of b :" << b << endl;

   swap(a, b);

   cout << "After swap, value of a :" << a << endl;
   cout << "After swap, value of b :" << b << endl;

   return 0;
}
void swap(int &x, int &y)            //no need to use pointer ! in c++ we can pass address like this
{
   int temp;

   temp = x;
   x = y;
   y = temp;

   return;
}




output:


Before swap, value of a :100
Before swap, value of b : 200


After swap, value of a :200
After swap, value of b : 100