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 do you mean by reference counts, Q. If each the access rights to an o...

Q. If each the access rights to an object are deleted the object can no longer be accessed. At this stage the object should also be deleted and the space it occupies should be ret

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

Mutual exclusion, With software algorithms for mutual exclusion, such as De...

With software algorithms for mutual exclusion, such as Dekker's algorithm, Peterson's algorithm, or Lamport's bakery algorithm, note that optimizing compilers and out-of-order exec

Graph - plotting job, This exercise uses a graph-plotting program ( gnuplot...

This exercise uses a graph-plotting program ( gnuplot ) to convert tabular data into an image. This is a technique that is very widely used to visualize scientific data; with app

What is page fault, Problem: a) The CPU can access 2 storage devices di...

Problem: a) The CPU can access 2 storage devices directly. What are these 2 storage devices? b) Define 2 key issues involved in memory management. c) How do processes sha

Activities of an operating system, Q. What are the five main activities of ...

Q. What are the five main activities of an operating system in regard to process management? Answer: a. The creation as well as deletion of both user and system processes

Describe the possible rmi invocation semantics, Question: (a) Briefly d...

Question: (a) Briefly discuss and describe the possible RMI invocation semantics. (b) (i) What is data marshaling? (ii) Explain the role of a remote object reference dur

What is critical section problem, What is critical section problem? Con...

What is critical section problem? Consider a system consists of 'n' processes. Every process has segment of code called a critical section, in which the process might be changi

Explain multithreading operating system, Multithreading - Operating system...

Multithreading - Operating systems that permit different parts of a software program to run concurrently. Operating systems that would come into this category are: Linux UNI

Explain about deadlocks, Q. Explain about Deadlocks? Deadlocks for (...

Q. Explain about Deadlocks? Deadlocks for (int i = 0; i // first find a thread that can finish for (int j = 0; j if (!finish[j]) { boolean temp = true; for

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