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

Programable clock modes in computer systems, Ask question #Minimuexplain th...

Ask question #Minimuexplain the programable clock modes in a computer system m 100 words accepted#

List the various file attributes, List the various file attributes. A f...

List the various file attributes. A file has particular other attributes, which vary from one operating system to another, but typically having of these:  Name, identifier, typ

Memory management, with aid of diagram describe 2 types of fixed partition ...

with aid of diagram describe 2 types of fixed partition allocation used in operating system

Obelia, what do obelia eat and how do they feed

what do obelia eat and how do they feed

Subject: system analysis (2000 word), Overview: In this assignment, you are...

Overview: In this assignment, you are going to perform a system analysis and design of a membership and facility management system of a gymnasium of given case study Task: You are

What is graceful degradation, What is graceful degradation? In multipro...

What is graceful degradation? In multiprocessor systems, failure of single processor will not halt the system, but only slow it down by sharing the work of failure system by ot

What are the issues in designing a network-fault tolerance, Fault tolerance...

Fault tolerance : Machine failures, Communication faults, storage device crashes, and decays of storage media must be tolerated by the system to some extent. A fault tolerant sy

Memory management, example of first fit best fit and worst fit

example of first fit best fit and worst fit

Steps to run a program on a completely dedicated machine, Q. List the four ...

Q. List the four steps that are essential to run a program on a completely dedicated machine. Answer: a) Reserve machine time b) Manually load program into memory c)

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