Chapter 9, Problem 57RQE

Program Plan Intro

Pointer:

Pointer, the name itself references the purpose of the pointer. Pointers point to a location in memory.

• Pointer is a special type of variable to store the address of the memory location, which can be accessed later.
• If an asterisk “*” operator is present before the variable, then that variable is referred as pointer variable.
  • It is also called as dereferencing or indirection operator.
• Pointer is just a type of variable that stores the addresses of other variables.
• Using pointers, we can access the address of a variable; the data stored in that variable can be retrieved.

Syntax of pointer variable declaration:

<variable-type> *<variable-name>;

Example for pointer variable declaration:

//definition of pointer variable

int *ptrvar;

Where,

• int is the variable type.
• * ptrvar is the pointer variable name.

Pointer will allow the user to indirectly access and manipulate the data contents of the variable. A pointer variable will hold the address of the data contents.

Note:

• When the symbol “&” is placed prior the pointer variable, it will hold address of the pointer variable.
• When the symbol “*” is placed prior the pointer variable, it will hold the value of the pointer variable.

Purpose of “new” operator:

The main purpose of the “new” operator is to dynamically allocate memory. Dynamic memory allocation is process where an individual chunk of memory space is allocated by the compiler that is sufficient for the storage of variables. This kind of allocation is possible with pointer variables.

Example:

Consider a pointer variable of type integer needs to be allocated dynamically and it can be made possible using new operator as shown below:

//null pointer declaration

int *myptr = nullptr;

//dynamic allocation of memory

myptr = new int;