A pointer is a variable that holds an address. Every variable declared in a program has two components:

> Address

> Value

C++ has two unary operators for referring to the components of a variable. The first operator, '&', known as the address operator returns the address of the variable. The operator '&' is followed by a variable name. The second operator, '*', known as the indirection operator returns the value stored in any address in memory. The operator * is followed by an address of the variable.

Consider the following example:

void fn()
{
int i = 10; //Statement 1
int *ivar; //Statement 2
ivar = &i; //Statement 3 - ivar now points to i
}

In the example, ivar is a pointer. Notice that the declartion of ivar in Statement 2 is preceded by the operator '*'. Pointer variables are declared like normal variables except for the addition of the unary operator '*'. Since a pointer stores the address of another variable, notice that in Statement 3, ivar stores the address of the variable i.

The example can be explained in a better way by referring to the following diagram(refer Figure 5.1).

 

Figure 5.1 Storing Value 10 in the Address Pointed at by iVar