Pointer in c language

The Pointers in c language programming is a variable that points to the address of another variable. The Pointer in the C language  is used to indicate the memory randomly for example at the run time. pointer variable strength be comfortableness to the any of data type such as int for digits, float for decimal, char,double character, short etc.The computer science the programming language object, whose value refers to another values stored elsewhere in computer memory using its memory address. A pointer references the location in the memory, and achieving the value stored at that location is known as dereferencing pointer. The Pointer Syntax:data type*var name for example int *p; char *p;.

KEY POINTS TO REMEMBER The POINTERS IN The C

1.  Size of any pointer is 2 byte(8 bits).
2.  The Pointer addition, multiplication,division are not allowed.
3. If the pointer in the C language  is assigned to NULL value then , it means it is indicating to nothing.
4. 2  pointers can be deducted or reduced to know how much  elements are present between these two pointers.
5. *  sign is used to achieve the value of the variable that pointer is pointing to.
6. & sign is used to get  address of the variable.
7. C pointer is initialized to null, for example int *p = null.
8. value of the null pointer is 0
9. medium variable store the value where as pointer variable stores the address of the variable.

Types of pointers

Different types of pointers in c language that are as follows.

1. Huge Pointers.
2. Near Pointer.
3. Far Pointer.
4. Complex Pointers.
5. Generic Pointers.
6. Wild Pointer.
7. NULL Pointer.
8. Dangling Pointer.

Huge pointer 

Huge pointer access whole the residence memory of the RAM for example which can access all sixteenth segments is known as a huge pointer. The huge pointer takes or reserves 32 bits or 4 byte in memory.

illustration of Huge Pointer in C Programming

#include<stdio.h>

int main()

{

      int a = 25;

      int huge *ptr_var;

      *ptr_var = &a;

      printf(“\nThe Size of Huge Pointer:\t\t%d”, sizeof(ptr_var));

      return 0;

}

Near Pointer

pointer which can indicate or point the  only 64 KB (kilo byte ) of data piece is known as near pointer. The pointer is near pointer does not achieved beyond data piece like graphics video memory or text video memory, etc. The Size of the near pointer is 2 byte.

#include<stdio.h>

int main()

{

      int a = 10;

      int near *ptr_var;

      *ptr_var = &a;

      printf(“%d”, sizeof(ptr_var));

      return 0;

}

Far pointer

Far pointer can point the whole the residence memory of RAM, for example which can be access all sixteenth piece  is known as far pointer.The Size of far pointer is 4 byte (32 bit) of data one bit can store one character of data in one byte there are 8 bits which can store 8 character of data or alphabets.

 Code example of Far Pointer in C Programming

#include<stdio.h>

int main()

{

      int a = 10;

      int far *ptr_var;

      *ptr_var = &a;

      printf(“%dThe size of “, sizeof(ptr_var));

      return 0;

}

Generic Pointers

The generic pointer is very useful when we are wanted to point any type of data the generic pointer is used to point the data.When the variable is initialized or declared as being the pointer to type (main functions of c language like ) void is known as the  generic pointer. Since we cannot have the  variable of type void, Generic pointer will not point to the  any data and therefore cannot be dereferenced. It is currently the pointer though, to use it we just have to cast it to next type of the pointer first.

Code example of Generic Pointer in C Programming

int
main()
{
int i;
char c;
void *the_data;
i = 6;
c = ‘a’;
the_data = &i;
printf(“Data points to the integer value %d\n”, *(int*) the_data);
the_data = &c;
printf(“Data now points to the character %c\n”, *(char*) the_data);
return 0;
}

Wild Pointer

The Pointer in the C language that has not initialized till its first use is known as the wild pointer. the wild pointer indicates to some random memory location in the c language where we want to point the data.

Code example of Wild Pointer in C Programming

#include<stdio.h>

int main()

{

      int *ptr;

      printf(“%p\n”, ptr);

      printf(“%d”, *ptr);

      return 0;

}

NULL Pointers

The Pointer which is declared with the NULL value is known as the NULL pointer,Null pointer in the pointer is the pointer which is pointing nothing.The Null pointer points the base address of any segment.The Null pointer is the micro constant which in prescribed in the following header files which are , stdio.h,etc.

Code example of NULL Pointer in C Programming

#include <stdio.h>

int main()

{

      int *ptr_f = NULL;

      int *ptr_s = 0;

      printf(“\nfirst Pointer:\t%p\n”, ptr_f);

      printf(“\nsecond Pointer:\t%p\n”, ptr_s);

      return 0;

}

The Dangling pointers is awaking when the object is deleted , without changing the value of the pointer, Therefore the pointer still points to the memory location of the deleted memory.

Illustration of Dangling Pointer

char *user_function(void)

{

char ch = ‘D’;

return &ch;

}