Address operator and pointers, Operating System

Assignment Help:

  We are use to using variables within C without thinking about where they are stored. Most variables are dynamic i.e. can change, therefore they are stored in Ram, unlike a program once developed is static i.e. doesn't change; this is often storage in EPROM or Rom. We can directly access the address where the variable is stored by means of the address operator '&' .This returns the address of the variable followed i.e.

printf("The address of var A is %lx and the contents of var A is %x",&a,a) 
 
This address is often fixed by the compiler and cannot be altered easily, very often we want initialize the address of a variable and vary it, C uses the concept of the pointer to handle this. A pointer is a variable which holds an address (This is in fact an address register on the 68Hc11 i.e. X, Y). We can explicitly load up the variable with any number (address which we like) and perform simple mathematical functions on it i.e. add, mul, sub etc. In order to declare the variable as a pointer we need to prefix it with a * in its declarations i.e.

      int *point;  
      char *point; 
      float *point;

The type of pointer  used describes the size of the data to be read  i.e. a char pointer reads 7 bits of data , unsigned char 8 bits i.e. (some programmers use sizeof function to get actual machine size).

    char * point  == 7 bits
     unsigned char * point  == 8 bits
     int * point  == 15 bits
     unsigned int  * point  == 16 bits
     float * point  == 31 bits
     unsigned float  * point  == 32 bits


Related Discussions:- Address operator and pointers

DOS, Ask question #Minimum 500 words accepted#

Ask question #Minimum 500 words accepted#

What are the advantages of linked allocation, What are the advantages of Li...

What are the advantages of Linked allocation? The benefits are a. No external fragmentation b. Size of the file does not require to be declared

What is a client server system, What is a client server system? Central...

What is a client server system? Centralized systems proceed as server systems to satisfy request generated by client systems Server system is able to be broadly div

Explain memory management using link lists, MEMORY MANAGEMENT USING LINK LI...

MEMORY MANAGEMENT USING LINK LISTS The first one is for showing it is process or hole, second is for starting address and third is for length of the process and last is a point

Determine the task of the pass ii in a two-pass assembler, Determine the ta...

Determine the task of the Pass II In a two-pass assembler Synthesize the target program is the task of the Pass II

Memory Management Problems, Sir i want formulas in Memory management starti...

Sir i want formulas in Memory management starting from paging till the demang paging in a easy manner for solving problems in competitive exams

Scheduler that select process from secondary storage device, A scheduler th...

A scheduler that selects processes from secondary storage device is known as                    Medium term scheduler is a scheduler that selects processes from secondary stor

Roles of operating systems, Describe Three major roles of operating systems...

Describe Three major roles of operating systems in business computer systems

File management, approaches to identify free memory area in a heap

approaches to identify free memory area in a heap

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd