What Is Near Pointer?

The Pointer which can point only 64KB data segment or segment number 8 is known as near Pointer. That is near pointer cannot access beyond the data segment like graphics video memory, text video memory, etc. Size of near pointer is two bytes. With help keyword near, we can make any pointer as near Pointer.

Examples:

#include<stdio.h>           int main() {          int x=25;          int near* ptr;           ptr=&x;          printf(“%d”,sizeof ptr);          return 0; }

Output: 2

(2)

#include<stdio.h> int main() {   int near* near * ptr;   printf(“%d”,sizeof(ptr),sizeof(*ptr));   return 0; }

Output: 2 2

Explanation: Size of any type of near pointer is two bytes. Near pointer only hold 16 bit offset address. Offset address varies from 0000 to FFFF (in hexadecimal). In printf statement to print the offset address in hexadecimal, %p is used.
Example:

#include<stdio.h> int main() {      int i=10;      int *ptr=&i;     printf("%p",ptr);     return 0; }

Output: Offset address in the hexadecimal number format. %p is also used to print any number in the hexadecimal number format. Example:

#include<stdio.h> int main() {    int a=12;   printf("%p",a);   return 0; }

Output: 000C Explanation: Hexadecimal value of 12 is C. Consider the following two c program and analyze its output: (1)

#include<stdio.h> int main() {      int near * ptr=( int *)0XFFFF;      ptr++;      ptr++;     printf(“%p”,ptr);    return 0; }

Output: 0003

(2)

#include<stdio.h> int main() {       int i;       char near *ptr=(char *)0xFFFA;       for(i=0;i<=10;i++){       printf("%p \n",ptr);       ptr++; } return 0; }

Output:

FFFA   FFFB  FFFC  FFFD  FFFE   FFFF

0000    0001    0002    0003    0004

Explanation: When we  increment or decrement the offset address from maximum and minimum value respectively then it repeats the same value in cyclic order. This property is known as cyclic nature of offset address. Cyclic property of offset address. If you increment the near pointer variable, then moves clockwise direction If you decrement the near pointer, then moves anti clockwise direction


What is the default type of pointer in C?

Answer: It depends upon the memory model.

Posted in: C faq