Web | This Site

C++ Basics
C++ Object Oriented
C++ Advanced
Java Useful References
Java Useful Resources
Selected Reading
© 2011 TutorialsPoint.COM

| Home |  | References |  | Discussion Forums |  | About TP

# C++ Pointer to Pointer (Multiple Indirection)

A pointer to a pointer is a form of multiple indirection, or a chain of pointers. Normally, a pointer contains the address of a variable. When we define a pointer to a pointer, the first pointer contains the address of the second pointer, which points to the location that contains the actual value as shown below.

A variable that is a pointer to a pointer must be declared as such. This is done by placing an additional asterisk in front of its name. For example, following is the declaration to declare a pointer to a pointer of type int:

    int **var;

When a target value is indirectly pointed to by a pointer to a pointer, accessing that value requires that the asterisk operator be applied twice, as is shown below in the example:

    #include <iostream>

    using namespace std;

    int main ()
    {
       int  var;
       int  *ptr;
       int  **pptr;

       var = 3000;

       // take the address of var
       ptr = &var;

       // take the address of ptr using address of operator &
       pptr = &ptr;

       // take the value using pptr
       cout << "Value of var :" << var << endl;
       cout << "Value available at *ptr :" << *ptr << endl;
       cout << "Value available at **pptr :" << **pptr << endl;

       return 0;
    }

When the above code is compiled and executed, it produces following result:

    Value of var :3000
    Value available at *ptr :3000
    Value available at **pptr :3000

Advertisement

Online Image Processing

Indian Baby Names