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C programming interview questions are scary and spine-chilling for many. Yes, Friends! But a little prep can make you have vibes of repose and self-confidence. 

Are you pondering how to answer C programming interview questions

No Worries. 

Indeed, you have landed on the correct page. Assuredly, this article will navigate you on how to master the C programming interview questions.

Probably by now, you might have completed scouring job portals for openings, polishing your resumes, penning the covering letters, and hence passed the first round of job hunting. Finally, it is time to face the difficult task: Y’all’s Job Interview. 

Positively, get ready and scroll down to learn how to present yourself most professionally when you embark on your interview.

Hang in there and Break a Leg!

All about C Programming

C LANGUAGE

C is the most popular computer programming language, considered the mother language of programming languages.

Though its origin dates back to the early 1970s, C is still the most preferred language as it is a procedure-oriented program. 

All most all MNC companies use the C language due to its ease and flexibility.

On the other hand, it has expertise in low-level and high-level languages. While low-level languages construct system programming, high-level languages are necessary for application programming. 

Moreover, C language supports various data structures, operators, constructors, and loop constructs.

Additionally, the C program has numerous features and helps to write other applications. For this reason, even after the invention of several new languages, the C language towers above all and remains versatile.

So why wait? Let us learn how to answer the questions bombarded by the interviewer.

TOP 50 C PROGRAMMING INTERVIEW QUESTIONS YOU NEED TO MASTER

The phrase job interview scares even the top qualified and is more anxiety-inducing than watching a super-horror movie. Facing an interview needs proper planning and execution.

The Pre-requisites of an interview include-

Some of the fundamental things to remember when you go in for an interview: 

  • Firstly, research the company to learn its values, mission & vision, benefits, hiring process, etc.
  • Dress professionally, decently, and impressively!
  • Never over-talk or under-talk, 
  • Have honest conversations, honor the agreements that you make,
  • Be on time and ask questions, if any, 
  • Remit a thank you note if it is all accomplished.

Generally, preparation for C programming interviews includes general preparation and subject-specific preparation.

Did not get it? Let us know.

You can learn the entire C program, mug it, and reproduce it. But a hiring manager requires not a book nerd but a well-trained, well-mannered, and well-balanced person. For this reason, any interview moves from general to more specific aspects.

Let us see how!

General Aspects included in Preparing for C programming interview are: 

Most Common Questions of Interviewing –  

Q1. Tell me something about yourself.

Ans.     This open-ended question troubles anyone. Here, the interviewer may ask this to pave an easy way into an actual interview and also to know more about you in your words than your resume.

To answer this question, here is a tip – Relax and follow the W.A.P strategy, i.e Work, Academic, and Personal. 80% related to your previous work, 10-15%of your academic excellence, and the remaining about your personality. 

It may not be applicable for a fresher. In that case, concentrate on your academic excellence and projects that you accomplished while being a student or an intern.

Q2. How did you hear about this position/role/company?

Ans.     When asked this question, grab the opportunity to express your interest, curiosity, and excitement to work at this company. If someone referred you there, don’t forget to mention it because if some credible person from the same company vouches for your skills, it would be an advantage for you. 

Q3. What are your biggest strengths?

Ans.     For this question, never give a list of your strengths. Significantly, make it concise to three that may help you to excel at the job and 1 or 2 personal skills.

Confused? Chill. Here’s a tip that can help you. Depending on your job role at the company, pick from the following skills:

  • Analytical jobs – critical, analytical, and logical thinking, problem-solving abilities, and detail-oriented.
  • Creative jobs – creativity, open-mindedness, curiosity, and originality.
  • Management jobs – leadership, organization, persuasion, communication skills, and teamwork.
  • Hands-on-jobs – hard-working, motivated, punctual, multi-tasking, and problem-solving.
  • Communication jobs – communication skills, charisma, energy, witty, and social.

Likewise, after you pick the appropriate skills, add a situation or story that explains where you have used it before. Be honest, clever, and confident while answering.

Situational Job Interview Questions

Then the interviewer may put before you some situational questions like:

  • Why haven’t you… 
  • Why have you….
  • Are you…

Don’t panic…Situational questions help the interviewer assess how you used these soft skills earlier. Prepare yourself beforehand to be encountered with such questions.

Q4. Why did you decide to leave your previous/current job?

Ans. Here the interviewer wants to know whether you left for a good reason, got fired, estimate your nature such as an escaping mentality, or make a quick exit when things go wrong.

Your answers could be like

–        I felt monotonous because I had gained enough experience and wanted to try     

         something new.

–      The organization was too controlling and nitpicking. Whereas, I love going above and beyond the call of duty.

Be polite, honest, and see that the ball is in your court. Here make use of the W.H.E.A.T. strategy, i.e. 

  • Workplace successes – successful activities that yielded positive results, and kudos.
  • High stakes – been successful in crucial situations like tight deadlines
  • Experience – skills and distinctive experiences that set you apart from others.
  • Approach – your problem-solving strategies and ways to tackle a challenging situation
  • Temperament –your communication skills and negotiating capacity 

Behavioral Job Interview Questions – 

Finally, now that you mastered general and situational questions, let us peep into behavioral questions.

The interviewer, here, tries to look at your past performance and how you handle a crisis.

Q5. How do you deal with a stressful situation?

Ans. All in all, you need to tell the context/scenario explaining your challenge, what action you took, and what the result was. To be successful in this, use the S.T.A.R strategy, i.e.

  1. S – Situation – Set the context
  2. T – Task – Describe the stressful situation or challenge
  3. A – Action – List or describe the actions taken to tackle    
  4. R – Result – Describe the outcomes of your action

Given these points, we complete the questions usually asked in a general round.

I hope you gained some confidence to deflect the arrows shot by the interviewers.

In the light of the above discussion, let us now knuckle down to learn how to answer C programming interview questions.

C programming interview questions form the core of the technical round assessment. The interviewers go over with a fine-tooth comb to dissect your knowledge of C language programming and its core concepts.

Correspondingly, the below-mentioned questions are well researched to present you with the latest, updated, and most asked questions in C programming interviews which fall under three categories, i.e. Basic, Intermediate, and advanced levels.

Let’s check them out-

Basic C Programming Interview Questions for Novices

BASIC QUESTIONS OF C INTERVIEW

Q6. Why is C Language known as the mother of all Programming Languages?

Ans: Dennis Ritchie invented the C language in 1972 to overcome the problems confronted by BASIC, B, and BPCL languages. By 1980, this became the most used language for mainframes, micro, and minicomputers. Further, many languages are designed based on C Language. Hence, it is known as the mother of all languages.

Q7. Name the four categories of C programming language.

Ans. The categories are – 

  • Basic data types – Further divided into integer and floating-point types
  • Derived data types – defines variables and assigns discrete integer values only
  • Void data types – no value is available for this date type
  • Enumerated data types -Array types, pointer types, union types, function, and structure. 

Q8. What is a stack?

 Ans. A stack is a type of data structure where data is stored in stacks using the First In Last Out (FILO) approach. Only the top of the stack is accessible at any given instance. To retrieve the data, extract the upper part of the data first. Then the data stow inside the stack can be retrieved later. 

Q9. What do you mean by PUSH and POP?

Ans. Storing data in a stack is referred to as a PUSH. While retrieving the data is referred to as a POP.

Q10. How do you insert quote characters (‘ and “) into the output screen in C programming? 

Ans. Explicitly, quotes are a part of a printf statement. To insert the quote character into the output, use the format specifiers \’ and \” for single and double quotes pro rata. It is a common problem faced by the fresher. 

Q11. What is the difference between the = symbol and == symbol? 

Ans. Mathematical operations often use the = symbol. To assign a value to a given variable, we use the = symbol. Alternatively, the == symbol is a relational operator that compares two values. = and == are familiarly known as “equal to” or “equivalent to.”

Q12. What is the modulus operator? 

Ans. The modulus operator opens the remainder of a division which uses the percentage (%) symbol. For example, 17 % 4 = 1, meaning when you divide 17 by 4, the remainder is 1.

Q13. Do you know the function of s++ and ++s?

Ans. s++ is a single machine instruction that augments the value of s by 1, Post increment. However, we use ++s to carry out pre-increment. 

Q14. What do you understand by calloc()?

Ans. In memory allocation calloc() is a dynamic function. It loads all the memory locations assigned to it with 0 value.

Q15. What is a token?

Tokens are the individual elements of a program. There are Six types of tokens in the C language. They are as follows:

  • Identifiers
  • Keywords
  • Operators
  • Constants
  • Strings, and
  • Special Characters

Q16. What is a C language’s built-in function?

Ans. Most commonly known as library functions, the C language provides the Built-functions to ease the programmers’ work by assisting them in doing some regular predefined tasks. 

For instance, for print output or want of a programming terminal, we use printf() in the C program.

Most commonly used built-in functions in C are printf(), sacnf(), strcat, strcpy, strlwr, strcmp, strlen, strlwr, etc.

Q17. Tell me about the Header Files.

Ans. Indeed, C programming provides some standard header files. The function of Header files is to do mathematical or logical calculations or even print the output to the console or files. For example, the stdio.h header file has the relevant code for printing the output to the console or its associated code. Hence, stdio.h code has to be incorporated upfront in the program for its execution.

Q18. Is there any difference between text files and binary files? 

Ans. The Text files contain data that humans can easily understand, such as numbers, letters, and other characters. Whereas, binary files contain language that only computers can interpret such as 1s and 0s.

Q19. What is Dangling Pointer Variable in C Programming? 

Ans: A Pointer points to the memory location of an existing variable in C Programming. Explicitly, a Dangling Pointer Variable is the Pointer that points to the same memory location even after it got deleted. 

Q20. What are the valid places for Break Control Statement application?

  • Ans: The places valid for the Break Control statement application are Switch Control Statements and inside a loop.

Intermediate C programming Interview Questions

Q21. Can you compile or execute a C program in the absence of a main()?

Ans: Notably, a program can be compiled but cannot be executed. To execute any C program, main() is required without fail.

Q22. Define <stdio.h>.

Ans. Stdio.h is a header file in C that contains prototypes and definitions of commands such as scanf and printf.

Q23. State the features of C Programming Language.

Ans: C programming is a top-notch language with bounteous built-in functions and operators to write variegated programs that are efficient and fast. The following are the features of the C language.

FEATURES OF C LANGUAGE

 Q24.  Mention different types of decision control statements.

Ans. In C language, decision control statements are if, if else, and nested if. There are three types of decision-making control statements in the C language. They are,

  1.  if statements
  2.  If….else statements
  3.  nested if statements

The following table explains the Syntax for each C decision control statement.

Decision control statementsSyntax & Description
 If statementSyntax:
 if (condition)
 { Statements; }
Description:
 Here, if condition is true, then the respective
block of code is executed.
 if…else statementSyntax:
 if (condition)
 { Statement1; Statement2; }
 else
 { Statement3; Statement4; }
Description:
 Here when the condition is true, a group of statements
is executed. Else part statements are executed if condition is false.
nested if statementSyntax:
 if (condition1){ Statement1; }
 else_if(condition2)
 { Statement2; }
 else Statement 3;
Description:
Here, if condition 1 is false, then condition 2 is checked and statements are executed if it is true. If condition 2 as well gets failure, then else part is executed.
Decision Control Statements in C Programming

Q25. What are an r-value and l-value?

Ans.  

  • A data value stored in memory at a given address is “r-value”, which is an expression with no value assigned to it. Hence, it exists only on the right side of an assignment operator(=).
  • “l-value” frequently referred to as an identifier, is a memory location used to identify an object, and it exists on either the right or left side of an assignment operator(=).

Q26. Explain the difference between ‘g’ and “g” in C.

Ans. In C programming language, single-quoted variables are termed as the character, while double-quotes variables are termed as a string. The string variables end with a null terminator. So this makes it a two-character array.

Q27. What is a File structure?

Ans. The file structure links the operating system and a program. The header file “stdio.h” defines the file and contains information about the file in use like its current size, memory location, and a character pointer to point the character that is currently in use. Thus, when we open a file it establishes a link between the program and the operating system.

Q28. Explain enum with an example.

Ans. An enum is a short form of “enumerations” which means “specifically listed.”

Being a special “class” Enum represents a group of constants (final variables which are unchangeable variables). Instead of class or interface, use the enum keyword to create it, also use a comma to separate constants, and notably, constants should be in uppercase letters.

Example:

Example for enum

Use Dot syntax to access enum constants:

       Level myVar = Level.MEDIUM;

Q29. How to declare a Function in C Language?

Ans: Declaring a function in C language is as follows,

    1      return_type function_name(formal parameter list)

2       {

3       Function_Body;

   4       }

Q30. What is toupper()? Explain with an example.

Ans. toupper() is a function that converts lowercase words/characters into upper case.

  1        #include&lt;stdio,h&gt

  2        #include&lt;ctype

  3        Int main()

  4        {

  5        Char c;

  6        c=a;

  7        Printf(“%c after conversions %c”,c, toupper/base

  8        c=B

  9        Printf(“%c after conversions %c”, c, toupper(c));

 //Example

//Output:

a after conversions A

 b after conversions B

 Q31. Give an example of a type of entry and exit controlled loop in C programming.

Ans. – We check Entry controlled loop condition at the beginning. Example: For loop. 

– On the contrary, the check for the Exit Controlled loop is at the end. Example: do-while loop. 

Here the loop runs at least once.

Q32. What are the applications that are written in C language?

Ans. C language helps to write numerous applications like system programming, application programming, operating systems, compilers, development of interpreters, graphics, general utilities, etc. 

Q33. Summarize data types.

 Ans. Data types are the ways and means how the language programmers enter, store, and engineer the data in the program. Uniquely, C has a variety of data types, mainly classified into three types.

  • Primary data types – Eg: int, char, float, and void
  • Derived data types – Eg: arrays, functions, and C-pointers
  • User-defined data types – usually a combination of data types or heterogeneous data types

Q34. Name the operators in C.

Ans. Generally speaking, Operators in C are the symbols that do mathematical or logical operations on data. Different categories of operators present in C are:

  • Arithmetic Operators
  • Logical Operators
  • Relational Operators
  • Bitwise Operators
  • Assignment Operators, and 
  • Ternary or Conditional Operators

Q35. What are Constants in C?

Ans. In C language, the Constants are entities or values whose value does not change during the course of the program. Constants can be classified as – primary and secondary constants that can further be divided into subtypes as shown in the figure below:

CONSTANTS IN C

Q36. What is recursion in C?

Ans. Recursion or recursive function is where a function calls itself. 

Q37. What are Preprocessors in C?

Ans. The programs that process the input data taken from another program, produce output, and send it to the compiler are known as Preprocessors. The C preprocessor is also known as CPP and is a macro preprocessor.

PREPROCESSORS IN C

Advanced C programming Interview Questions

The following are the C programming interview questions for the aspirers with advanced C program knowledge. Check them out!

Q38. What is the stack area?

Ans. Arguments and local variables of a method are stored in a stack area. Until terminated it stays in memory.

Q39. Can we compile a program without a main() function?

Ans. Yes, using Macro we can compile a program without the main() function.

Example:        #include<studio.h>

#define abc main

int abc ()

{

printf(“Hello World “);

return 0;

}

Q40. What are the Keywords in C?

Ans. Keywords in C are the reserved words that cannot be used as a constant name, variable name, etc. Explicitly, there are only 32 keywords in the C language that are as follows:

autoBreakcasecharconstcontinuedefaultdo
doubleelseenumexternfloatforgotoif
intlongregisterreturnshortsignedsizeofstatic
structswitchtypedefunionunsignedvoidvolatilewhile
KEYWORDS IN C

Q41. What are literals in C?

Ans. In general, Literals represent fixed values that are not modifiable. They are the constant values assigned to the constant variables.

For instance, const int =8; is a constant integer expression in which 8 is an integer literal.

There are four types of literals in C. They are as follows:

  • Integer literal
  • Float literal
  • Character literal
  • String literal

Q42. What is the acronym for ANSI?

Ans. The acronym ANSI stands for “American National Standard Institute.” This organization maintains an array of disciplines like computer languages, photographic film, data encoding, safety, mechanical parts, and more.

Q43. What is typecasting?

Ans: The process of converting one data type into another data type is known as typecasting. To store the floating type value to an int type explicitly requires converting the data type into another data type.

Syntax:

1              (type name) expression;  
TYPECASTING

Q44. How can you print a string with the symbol % in it?

1              printf(&amp;ldquo;there are90%%chances of rain tonight&amp;rdquo;);  
STRING WITH THE SYMBOL %

Ans: In C for the symbol % there is no escape sequence provided. So, to print % we should use ‘%%’ as depicted below:

Q45. What is a union?

Ans. The union is a user-defined data type. It allows storing myriad types of data in a solitary unit. However, it holds the memory of the largest member only. In a union, as all the members are allocated one common space, one can access only one variable at a time.

Syntax:

union union_name  

{  

Member_variable1;  

Member_variable2;  

.  

.  

Member_variable n;  

}[union variables]; 

Q46. Explain the # pragma directive.

Ans: The Pragma Directive is a preprocessor directive used to turn on or off certain features. Types –

  1. #pragma startup- helps to specify functions called upon program startup.
  2. #pragma exit allows specifying functions called upon program exit.
  3. #pragma warn warns the computer to suppress any warning or not.

Q47. What is Bubble Sort Algorithm?

Ans: A simple sorting algorithm called Bubble sort algorithm that repeatedly passes through the list until the list is sorted. While passing it compares adjacent elements and swaps them if found in the wrong order.

Q48. What is an infinite loop?

Ans. As the name indicates the loop runs continuously for an indefinite number of times.

Infinite for Loop:

for(;;){  
//code to be executed  
}  

Infinite While Loop:

while(1){  
//code to be executed  
}  

Infinite Do-While Loop:

do{  
//code to be executed  
}while(1);  

Q49. Assume that in a certain block global variable and local variable had the same names. Now, can you access a global variable from that block where local variables are defined? 

Ans. No. As the local variable always gets preference it is not possible in C to access global variable.

Q50. How to override a defined macro?

Ans. We can use #ifdef and #undef preprocessors to override a defined macro. It is as follows:

  • #ifdef A
  • #undef A
  • #endif
  • #define A 10

If macro A is defined, it will be first undefined using undef and later defined again using define.

Ah! This sums up our interview questions.

Intend to step-up your C skills? Or wish to learn C?

If your answer is yes, then join the best institutes that coach you to become a C professional.

Here are the Top institutes of India.

  1. Henry Harvin
  2. Udemy
  3. Coursera
  4. Codeacademy
  5. Codingninjas
  6. Vector Institution
  7. Shiksha
  8. C++ Institute
  9. Besant Technologies
  10. Koeing Solutions

Let’s Wind Up

Well, with this we sum up the Top 50 C Programming interview questions that you need to master.   I hope these C Programming interview questions indeed helps you to face your upcoming interview with confidence. Further, if you want to polish yourself and abreast your knowledge, you may join the renowned institutes that teach the C language, attend or watch online tutorials and take some mock interview sessions.

Float a trial-balloon; make a dry run because there is always a light at the end of each tunnel.

Recommended Reads:

FAQs

Q.1. What are the prerequisites of a job interview?

Ans. The Pre-requisites of an interview include-
·         Firstly, research the company to learn its values, mission & vision, benefits,
the hiring process, etc.
·         Dress professionally, decently, and impressively!
·         Never over-talk or under-talk, 
·         Have honest conversations, honor the agreements that you make,
·         Be on time and ask questions, if any, 
·         Remit a thank you note if it is all accomplished.

Q.2. What is a C Program?

Ans. Though its origin dates back to the early 1970s, C is still the most preferred language as it is a procedure-oriented program. All most all MNC companies use the C language due to its ease and flexibility. On the other hand, it has expertise in low-level and high-level languages. While low-level languages construct system programming, high-level languages are necessary for application programming. 

Q.3. Why C is considered the Mother of all programming languages?

Ans. C is the most popular computer programming language, considered the mother language of programming languages. C language supports various data structures, operators, constructors, and loop constructs. The C program has numerous features and helps to write other applications. For this reason, even after the invention of several new languages, the C language towers above all and remains versatile.

Q.4. Why learn C Program?

Ans. For many programming languages, ‘C’ is the foundation language. Surely, learning ‘C’ as the main language simplifies the learning of other programming languages. It shares the same concepts and can be used widely in various applications. Being a simple language it provides faster execution. The avenues for a ‘C’ developer in the current market are high. Hence, the C language is worth learning.

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