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

Fibonacci sequence, #questionThe Fibonacci sequence is the series of number...

#questionThe Fibonacci sequence is the series of numbers 0,1,1,2,3,5,8,… Formally, it can be expressed as: fib0 = 0 fib1 = 1 fibn = fib n-1 + fib n-2 Write a C program u

Queing theory, how to solve queing theory step by step

how to solve queing theory step by step

Explain the advantages and drawback of multiple processes, Explain the Adva...

Explain the Advantages and Drawback of Multiple Processes Application architected to take advantage of multiple processes will certainly see performance gains. Functions and Fe

Bounded and unbounded buffer, Ask question #Minimum 100 difference between ...

Ask question #Minimum 100 difference between bounded and unbounded buffer words accepted#

Define lru page replacement policy, Define ‘LRU’ page replacement policy ...

Define ‘LRU’ page replacement policy LRU is Least Recently Used page replacement policy.

Operating system design, You are required to study the important system com...

You are required to study the important system components, including important data structures, important functions and algorithms, and the various organizational, structural, logi

Explain process states in the unix system, Process States A total of n...

Process States A total of nine states are acknowledged by the UNIX system. They are like as follow: User running                                                   Executing

What is the lower bound on the numeral of page faults, Q. Presume that you...

Q. Presume that you have a page-reference string for a process with m frames (initially all empty). The page-reference string has length p along with n distinct page numbers

Explain User-level threads (ult), USER-LEVEL THREADS (ULT) In this lev...

USER-LEVEL THREADS (ULT) In this level the kernel isn't aware of the existence of threads -- All thread management is complete by the application by using a thread library. Th

Producer - consumer system, In this exercise we are going to use  pthread()...

In this exercise we are going to use  pthread()to simulate the dynamics between a warehouse, factory and retail. The factory produces product by using parts supplied by the warehou

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