When we declare a variable in
C/C++ etc.. like int x or int y , it tells the compiler to
reserve the space of two bytes(Size depends on OS Platforms/Compilers ) in the
memory to store the integer type value and identify the storage location in the
memory by 'x' or 'y' etc.
So every variable has three
properties 1. Identifier (Name like x
or y) 2. Value(x=10 or y=15 etc.) 3.
Its address (hexadecimal) in the Temporary Memory i.e. RAM. Since compiler
makes our job simpler by giving an opportunity to know only the variable’s name
and its value then in normal situation we have no need to worry about the
location or address of the variable. But in advanced programming and certain
types of problems we have to handle and use the address of variables. So the
concept of Pointers solves this problem.
We can say Pointer Definition
as "Pointers are those variables
which holds the address of another variable”. In C/C++ we can see the “Address” or “Memory Location Number” of any variable by using "&"
i.e. if we declare a variable 'x' eg: int x; we can see its address by printf
statement as follows printf("\n %d", &x);
Now to handle the address of
variables we have the facility to declare the Pointer variable like this int *p; this statement tells the
compilers to reserve the space in memory to store the address of integer type
variable. To assign the address of any integer type variable to 'p' we have to write the statement like
p = &x;
Example Program:
 |
| Pointers in C |
void main()
{
int
x = 34; //variable declaration and definition.
int
*p; //pointer declaration.
/* p is a pointer which points to a
integer variable or ‘p’ is a pointer which holds the address of
an integer variable.. */
p = &x; //Assigning the address of variable ‘x’ to pointer ‘p’.
printf("Address of variable x is : %x",p);//prints the address of variable ‘x’.
here %x displays Address in Hexa decimal format.
}
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