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

Explain process scheduling, Explain Process scheduling Process scheduli...

Explain Process scheduling Process scheduling consists of the subsequent sub-functions: 1.      Scheduling : Selects the process to be implement next on the CPU 2.      D

Deadlock prevention-resource allocation graph allocation, Explain Deadlock ...

Explain Deadlock Prevention-Resource allocation graph allocation Resource allocation graph algorithm :  Using this algorithm we are able to actually know if there exists in th

Explain about functions of operating system, Q. Explain about Functions of ...

Q. Explain about Functions of Operating System? Functions of Operating System Operating system performs 3 functions as follows: 1.  Convenience:   Operating System mak

Address operator and pointers, We are use to using variables within C witho...

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

Explain hierarchical paging method, Hierarchical paging method Most mo...

Hierarchical paging method Most modern computer systems maintain a large logical-address space. In this situation the page table itself turns into excessively large. To remedy

Digital circuits and design , 1. Draw a schematic diagram of a CMOS inverte...

1. Draw a schematic diagram of a CMOS inverter and explain its operation. 2. Draw schematic diagrams of CMOS NAND and NOR gates, and explain their operation. 3. Explain what

Does windows xp offer any user-mode processes, Q. Does Windows XP offer any...

Q. Does Windows XP offer any user-mode processes that enable it to run programs developed for other operating systems? Describe two of these subsystems. Answer: Environmental

define system calls, When a computer is started on, the program that execu...

When a computer is started on, the program that executed first is named the ''operating system.'' It controls pretty much all applications in the computer. This adds who logs in, h

Deadlock resoloution technique, justify the role played by the operating sy...

justify the role played by the operating system in managing the process to avoid deadlock

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