Pointers in C++

Pointer To Integers & Pointer To Pointer

**************************************************************************************

#include<iostream.h>

void main()

{

int var1=11;

int *ptr;

// pointer to integer

// dealing with pointer *ptr and integer vriable var1

ptr=&var1;

// Errors

//      *ptr=&var1;

//       ptr=var1;

//       var1=&ptr;

cout<<"Adress that pointer ptr is holding=                                      "<<ptr;

cout<<endl<<"Value of integer variable var=                                   "<<var1;

cout<<endl<<"Adress of var1 vriable using adress operator=              "<<&var1;

cout<<endl<<"Value of that variable for those this pointer is assign=  "<<*ptr;

cout<<endl<<"Own Address of pointer ptr=                                      "<<&ptr;

//dealing with pointer to pointer

int **ptr1;

//   Errors

// ptr1=var1;

// ptr1=ptr;

// ptr1=&var1;

// ptr1=&*ptr;

ptr1=&ptr;

cout<<endl<<"Adress that pointer** ptr1 is holding=            "<<ptr1;

cout<<endl<<"Adress that pointer* ptr is holding=               "<<*ptr1;

cout<<endl<<"Own adress of pointer** ptr1=                       "<<&ptr1;

cout<<endl<<"Adress that pointer* ptr is holding=                "<<&ptr;

cout<<endl<<"Value of variable that adress is saved in ptr*= "<<**ptr1;

//  Derefrencing addresses

var1=3;

*ptr=4;        // use all these three one by one and see the change in output

**ptr1=5;

 cout<<endl<<"\n\t var1=3 *ptr=4 **ptr1=5\n";

cout<<endl<<"Adress that pointer ptr is holding=                             "<<ptr;

cout<<endl<<"Value of integer variable var=                                  "<<var1;

cout<<endl<<"Adress of var1 vriable using adress operator=              "<<&var1;

cout<<endl<<"Value of that variable for those this pointer is assign= "<<*ptr;

cout<<endl<<"Own Address of pointer ptr=                                   "<<&ptr;

cout<<endl<<"Adress that pointer** ptr1 is holding=                      "<<ptr1;

cout<<endl<<"Adress that pointer* ptr is holding=                         "<<*ptr1;

cout<<endl<<"Own adress of pointer** ptr1=                                "<<&ptr1;

cout<<endl<<"Adress that pointer* ptr is holding=                         "<<&ptr;

cout<<endl<<"Value of variable that adress is saved in ptr*=          "<<**ptr1;

}