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

What is dispatcher? explain, Questiion 1 What is RTOS? What are its requir...

Questiion 1 What is RTOS? What are its requirements? Questiion 2 Explain the structural elements of a real time system mode Questiion 3 What is kernel? Explain abo

What are the issues in designing a network, Normal 0 false fa...

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Cpu scheduling alogarithm program in javascript, a program that can do cpu ...

a program that can do cpu scheduling algorithm priority using javascript or php to display gaant chart and calculate waiting and average waiting time

What do you understand by “line balancing”? What happens if , What do you u...

What do you understand by “line balancing”? What happens if balance doesn’t exist?

Unsafe state, discuss unsafe state in operating system

discuss unsafe state in operating system

Illustrate advantages and inconveniences of klt, ADVANTAGES AND INCONVENIEN...

ADVANTAGES AND INCONVENIENCES OF KLT Advantages: the kernel be able to simultaneously schedule many threads of the same process on many processors blocking

What are the different types of semaphore?, What are the different types of...

What are the different types of semaphore? Principally the semaphore is able to be classified into two on the basis of their values a)      Counting semaphore: In counting s

Define an assembly language, Define an assembly language  Assembly lan...

Define an assembly language  Assembly language stands for a Low level programming language

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