Important C interview questions with answers

Mar 4 • Resources • 61513 Views • 21 Comments on Important C interview questions with answers

Learning C Language is the first important step that a science student take in the journey of their education. C language comprises of several small programs to even much large programs which can be learn easily. C language has been told as an easy language of learning and the programming concept in the world of computers. Different questions based on C programming are the hot topics and most asked questions that every interviewer asked during the recruitment of any organisation. Lets have a look over C interview questions with answers that has been asked in the various technical interviews-

C interview question and answer

C Language role

C Interview questions with answers

1. What is a pointer?
A pointer is a special variable, which stores the memory address. The ‘ampersand’ denoted by ‘&’ and the ‘dereferencing’ factor denoted by ‘*’ are the necessities of pointers. Ampersand in front of a variable gets its address and asterisk in front of a pointer gets its value.

2. What is null pointer?
Null pointer is a pointer which cannot point to anywhere in the program, but uninitialised pointer can point to anywhere in the users program. In C, if the pointer tried to access 0th location, operating system kills the running program because operating system does not allow to access 0th value.

3. Define function pointer?
The function pointer is the pointer which accesses the address of a function. The running program occupies some memory space. Both the executable compiled program code and as well as user variables works on function pointers.
In the C, each function has an address in a code segment.

4. What is volatile variable?
Volatile variables are those variables which alters the default way of the program.
The variable which do not change while compiling but are changeable during execution.

5.  Difference between global and static variable?
Static variables persist throughout the scope, but the lifespan is not throughout the program. Global variables persist throughout the scope of base blocks of memory that is their lifespan is throughout the program.

6.  What are the files automatically opened when C file is executed?
Standard in, standard out, standard error (stdin, stdout, stderr) are the files which are automatically opened when C file is executed.

7. Compare between array and pointer.
Array can allocate variables but cannot reallocate those variable if required.  Whereas the pointer was assigned to allocate variables and they can also relocate and also are resizable.

8. Define function prototype?
The function prototype is the prototype which depends on the following:
a. No. of input types
b. No. of outputs which are to be returned

9. Where the function pointers can be used?
The function  pointers can be used when if/switch statements are present,in late binding(variation tables) and to implement call backs activities.

10 What do you mean by #include<stdio.h>?
In C, the hash function # tells the compiler that a statement should be sent to the C preprocessor. The include looks after the new files and replace the contents of those files. and stdio.h will be valid only for the printf, scanf functions.

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21 Responses to Important C interview questions with answers

  1. nan says:


  2. Anonymous says:
  3. Anonymous says:
  4. Nanndhini says:


  5. Nanndhini says:


  6. Nanndhini says:


  7. Nanndhini says:
  8. Azhahesan says:

    BE computer science

  9. Ria Roy says:

    Differentiate between mallow and calloc function

  10. TARA KUMRI says:

    I Want basic interview questions of c, c++,java. I am a fresher candidate. So i have no idea about that.

  11. Sindhu Kumari says:

    guide me the questions which will be asked in tcs written

  12. veera says:

    i want detailed explained of pointers in c language
    can you send it to my above mentioned mail

  13. veera says:

    i want detailed explained of pointers in c language
    can you send it to my above mentioned gmail

  14. Narayani says:

    Dr Mahalingam college of engineering and technology

  15. SHAIK KALESHA says:


  16. shaik.chandhini says:

    i have complited my i am learning .net course …. but i have no complite knoledge in c . i have know little bit basic about c …my query is whenever i attend an interview on .net that time interviewer asks about c quesions are not ..

  17. Avinash Hari Patil says:

    I am last year engineering student, But I cant decide which is best field for my future as per knowledge

  18. RAVI BHARTI says:

    how i prepare myself for technical interviews round

  19. Aratrika Sengupta says:

    When dreaming for Software companies, C is one of the necessity to have a grip on. Thus this questions if not totally but will help you know the type mostly seeked by the interviewers.

  20. Anjali Dreamgirl says:

    These are basic interview questions which are being asked so practice this.

  21. Arpita Sardar says:

    I think it will be helpful for those people who want to take preperation for an interview that is mainly based on C Language…

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