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

Ipc, Explain in detail about ipc in linux

Explain in detail about ipc in linux

Evaluate the physical address, Compare between the one and two-dimensional ...

Compare between the one and two-dimensional memory organizations in terms of the  memory structure,  advantages, and disadvantages.  Which approach would better support the needs o

Define a daemon process , A daemon is a process that removes itself from t...

A daemon is a process that removes itself from the terminal and disconnected, executes, in the background, waiting for requests and responding to them. It may also be described as

Race condition, list the prevention of mechanism for race condition with op...

list the prevention of mechanism for race condition with operating system

Define instance, Define Instance. An instance is an administrative unit...

Define Instance. An instance is an administrative unit in which components of R/3 systems giving one or more services are grouped together.  The services offered by a case are

Crank-nicolson timestepping schemes, For the heat conduction problem, inves...

For the heat conduction problem, investigate the effects on the numerical solution of the following aspects: 1. non-uniform meshes with re?nement at both ends versus a uniform m

Architects applications by making use of multitasking, Architects Applicati...

Architects Applications by Making Use of Multitasking As the capability of computer hardware keeps increasing, operating systems are presented with overwhelming opportunities.

Cpu scheduling algorithm, Q. A CPU scheduling algorithm determined an orde...

Q. A CPU scheduling algorithm determined an order for the execution of its scheduled processes. Convinced n processes to be scheduled on one processor how numerous possible differ

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