Pointer is a memory variable, which can store the
address of
another
variable.
Pointers
can point other variables.
Normally,
when we declare some variables, some amount of memory
is allocated for those variables. These address
locations can be
pointed by pointers. The address will be in unsigned
integer form, ranging
from 0 to 65535. So pointers are always storing
unsigned integers only.If
you need to mention any pointer variable you should
use the unsigned integer
control string.
When
discussing pointers, we use the following notations.
&
- address operator
* - value at the address operator(Pointer
Operator).
-> - In-Direction Operator.
To
declare pointer variables
dataType
*PtrVariable;
eg:
int *p;
Uses
1.
Allows us to refer the memory locations directly.
2.
Improves the program speed
3.
Used in DMA (Dynamic memory allocaiton or Direct Memory Access)
4.
Used in Data Structures/File processing
5. Arrays/Strings
can be accessed thru pointers.
6.
Functions pass by reference is acheived by pointers
Note :
Variable Memory Size Control strings
int 2b %d or %i
char 1b %c
float
4b %f
double 8b %lf
long
int 4b %ld
unsigned
int 2b %u
Pointer
with in Structures:
===========================
If
you need to Access the Structure members by using Pointer
Variables,
By using indirection (->) Operator we can able to access.
Syntax
for Creating Pointer structure variable:
struct
structure-name *var1,*var2...;
If
you declared any structure variable as a pointer type, then if you
need
to intialize any members, Before initializing you should initialize
the
pointer structure variable.
Syntax
for Accessing members of structure:
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