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

Design a android application, As mentioned earlier, the game engine will b...

As mentioned earlier, the game engine will be used as the base of developing the Go game for the Android. This includes improving logic of the game, design good graphics and optim

Explain fifo page replacement in detail, FIFO page replacement This is...

FIFO page replacement This is the easiest page replacement algorithm. Here the 1 st page toward the inside is the 1 st to leave that is the oldest page leaves. To execute th

Dual Mode Operation, I am not getting what you have tried to describe here....

I am not getting what you have tried to describe here. Can you elaborate more about this, i will be thankful to you. Vinay

Lock revenue variable, Demonstrate that your program (include the program o...

Demonstrate that your program (include the program output as part of the final report) can produce the correct output with the following parameters. For each case comment if the ou

Any four types of operating system feature and structure, explain any four...

explain any four types of operating system feature and structure(design)

Virtual memory and paging, A- Consider a computer system that provides a vi...

A- Consider a computer system that provides a virtual memory space that consists of 8  pages. The physical memory contains 4 pages where the page size is 4Kbytes. Assume that at sp

Paging, protection in paging

protection in paging

Determine a critical section is a program segment, Determine a critical sec...

Determine a critical section is a program segment  Critical section is where shared resources are accessed

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