REFERENCE---  A reference variable is initialized first. A reference variable is defined to indicate a variable and that reference variable can't point to the another variable. References can not be NULL.

e.g of reference variable is:

#include <iostream>
 using namespace std;
 int main ()
 {   // declare simple variables 
  int a; 
  double d;

   // declare reference variables 
  int& r = a;
  double& s = d;

  a = 5;
  cout << "Value of a : " << a << endl;
  cout << "Value of a reference : " << r << endl;
  d = 11.7; 
  cout << "Value of d : " << d << endl;
  cout << "Value of d reference : " << s << endl; 

  return 0;
  }

output of above code is:

Value of i : 5
Value of i reference : 5
Value of d : 11.7
Value of d reference : 11.7

POINTERS-- With the help of pointers some tasks are performed more easily, some tasks can not be performed without pointers(dynamic memory allocation). A pointer is a variable that holds the memory address of another object.

Pointers are powerful because it allows us to access address and manipulate the data. If it is correctly used , it increases the performance and efficiency.

syntax of declaring pointer is:

e.g of pointer:

#include <iostream>

using namespace std;

int main ()
{
   int  var1;
   char var2[10];

   cout << "Address of var1 variable: ";
   cout << &var1 << endl;

   cout << "Address of var2 variable: ";
   cout << &var2 << endl;

   return 0;
}

output of above program is:

Address of var1 variable: 0xbfebd5c0
Address of var2 variable: 0xbfebd5b6