'Size of pointers' what does this mean ?

Replies

• 

  Ankita Katdare

  Pointer is a "variable" that stores the address of another variable, right?
  Whenever we declare any variable, a random block of memory is chosen and value will be stored in that memory location.
  Similars is the case with pointers!
  Use sizeOf operator to check the size of any pointer variable.
• 

  Alok mishra

  Ankita Katdare

  Pointer is a "variable" that stores the address of another variable, right?
  Whenever we declare any variable, a random block of memory is chosen and value will be stored in that memory location.
  Similars is the case with pointers!
  Use sizeOf operator to check the size of any pointer variable.

  clear , say there is a pointer variable which is 2 byte large in size so what i am asking is what are these 2 bytes ,size of the address the pointer is pointing to ,or size of block of memory the pointer is pointing to (but the size of memory block the pointer is pointing to might be larger than 2 bytes ) ?
• 

  Aadit Kapoor

  #include 
  #include 
  
  main()
  {
      int a = 12;  /* 4 bytes stored in memory system */
      int *p = &a; /* 4 bytes stores in memory system for p and now p is pointing to a variable */
  
      printf("Size of variable a = %d,Size of pointer variable p = %d\n",sizeof(a),sizeof(p)); /* Ouput :  Size of variable a  = 4 and Size of variable p = 4 */
  }

  pointer is noting but a variable that points to its type.For example int pointer variable will only point to int variables.
  But there is a void pointer which is like a generic pointer in c.It can contain any types of variables,but void pointers are not capable of pointer arithmetic operations.
• 

  Alok mishra

  Aadit Kapoor

  #include 
  #include 
  
  main()
  {
      int a = 12;  /* 4 bytes stored in memory system */
      int *p = &a; /* 4 bytes stores in memory system for p and now p is pointing to a variable */
  
      printf("Size of variable a = %d,Size of pointer variable p = %d\n",sizeof(a),sizeof(p)); /* Ouput :  Size of variable a  = 4 and Size of variable p = 4 */
  }

  pointer is noting but a variable that points to its type.For example int pointer variable will only point to int variables.
  But there is a void pointer which is like a generic pointer in c.It can contain any types of variables,but void pointers are not capable of pointer arithmetic operations.

  yes thats what i know but a statement in a book confused me .it(the book) was saying that pointer variables are 2 byte wide in DOS and 4 byte wide in windows/linux.
• 

  Anand Tamariya

  The size refers to the size of data type which in fact is different in DOS and other OSes. This is required by specification.
• 

  Aadit Kapoor

  Alok mishra

  yes thats what i know but a statement in a book confused me .it(the book) was saying that pointer variables are 2 byte wide in DOS and 4 byte wide in windows/linux.

  As Anand Bhaiya said it varies from different operating system.
• 

  Alok mishra

  Aadit Kapoor

  As Anand Bhaiya said it varies from different operating system.

  got it
• 

  najeeb88

  Thank so much for sharing your thought with your readers.
  
  
  #-Link-Snipped-#
• 

  Aadit Kapoor

  Can any one tell me what is hardware engineering?
• 

  Alok mishra

  Aadit Kapoor

  Can any one tell me what is hardware engineering?

  hardware engineering is mainly concerned with the establishment ,look after and maintenance of computer networks but also put focus on other hardware related issues related to power supply , computer components and peripherals etc .
• 

  Aadit Kapoor

  How to get started in hardware engineering?
• 

  Abhishek Rawal

  Aadit Kapoor

  Can any one tell me what is hardware engineering?

  Are you interested in maintaining hardware ? Something like 'troubleshooter' for computer hardwares ?
  Or you're rather interested in 'developing' hardware & communicating hardware using programming languages ?
  
  Note that both are very different domain & in my opinion, latter one is rather very much interesting than the other one.
• 

  Aadit Kapoor

  Abhishek Rawal

  Are you interested in maintaining hardware ? Something like 'troubleshooter' for computer hardwares ?
  Or you're rather interested in 'developing' hardware & communicating hardware using programming languages ?
  
  Note that both are very different domain & in my opinion, latter one is rather very much interesting than the other one.

  I am interested in developing hardware & communicating hardware using programming languages.
  How do i get started in this?
• 

  Aadit Kapoor

  I am currently learning C and Data structures.
• 

  Abhishek Rawal

  Learning programming languages is good & C is obviously good start. But don't start picking up languages one after another like all others do,stick with C/Embedded C.(Python & Vala is fun language too,just saying).Also avoid learning languages like Java or C++ for now.Learning these languages won't do anything wrong, but remember that you're dealing with hardware so it is better to consume time in learning & understanding basics of electronics & understanding hardware first, you can pick on other languages later.
  
  I am not in position in giving suggestions,as I am too a student myself & trying to march towards Embedded linux. But I can ask you to do same what I did :
  Understand Basics of electronics, Learn Digital logic design, Start learning 8086/80386 & Intel-51 family.
  Read Assembly language step-by-step Programming with Linux by Duntemann,awesome book!
  Fun part starts now,Buy arduino,RPi & start creating something.(I am in this phase now)
  
  What next ? well I don't know too, But I am planning to learn RTOS, Linux Kernel,GNU toolchain & ARM.
• 

  najeeb88

  najeeb88

  Thank so much for sharing your thought with your readers.

  Informative post.....
• 

  Aadit Kapoor

  Alok mishra

  yes thats what i know but a statement in a book confused me .it(the book) was saying that pointer variables are 2 byte wide in DOS and 4 byte wide in windows/linux.

  One more thing,pointers were introduced by operating system vendors,that is why it comes 2 and 4 in dos and windows respectively.