The variables that you have dealt with so far provide you with the ability to name a memory location in which you can store data of a particular type. The contents of a variable are either entered from an external source, such as the keyboard, or calculated from other values that are entered. There is another kind of variable that does not store data that you normally enter or calculate, but greatly extends the power and flexibility of your programs. This kind of variable is called a pointer.

What Is a Pointer?

Each memory location that you use to store a data value has an address. The address provides the means for your PC hardware to reference a particular data item. A pointer is a variable that stores the address of another variable of a particular type. A pointer has a variable name just like any other variable and also has a type that designates what kind of variables its contents refer to. Note that the type of a pointer variable includes the fact that it’s a pointer. A variable that is a pointer, that can hold addresses of locations in memory containing values of type int, is of type ‘pointer to int’.

Declaring Pointers

The declaration for a pointer is similar to that of an ordinary variable, except that the pointer name has an asterisk in front of it to indicate that it’s a variable that is a pointer. For example, to declare a pointer pnumber of type long, you could use the following statement:

long* pnumber;

This declaration has been written with the ...

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