Comprehensive Guide to C Programming Interview Questions and Answers

Interview questions based on the programming language C are standard at almost all of the world’s largest multinational corporations (MNCs). This article discusses interview questions that have become more common and important over the past few years. There is also a section about C Programming Interview Questions and Answers.


Dennis Ritchie made the c programming in 1972 at Bell Labs. Can use C programming for a wide range of projects. Even though it is old, many people still use it.

C is very close to UNIX because it initially made it to make the UNIX operating system.

Benefits of C Programming:

  • Effective and powerful language

C is a “portable assembler” used for low-level programming that can compile with many languages. The efficiency of the C programming language makes it easy to write code, making programs run faster. Because it is flexible, you can use many different libraries, such as those for computer vision (OpenCV), database management (SQLite), and graphical user interface (GTK+) (windowing toolkit).

There are benefits to the language’s origins as an implementation language, such as the fact that it was made by experts who had experience in writing programs on machines, that you don’t have to worry about misallocating memory, and that the language’s simplicity makes it easy to use.

  • Portable Language

In C Programming, it’s easy to bring your work with you. You don’t have to know how your machine’s memory is set up to write programs for it because it can be compiled with different compilers and run on most hardware platforms. You don’t need to know assembly to compile C code; the same is true for the group.

  • Built-in functions

Functions already built into C make it easier for software engineers to create software. The compiler automatically links in frequently used functions like scanf() and print () so that you can call them without having to be declared first. So that you can focus on your implementation, many libraries offer even more of these function calls.

  • Capacity to develop

One of the many good things about C is that you can add to it. Adding Java and Objective-C, among others, has made the language more powerful. Preprocessors like GCC and Clang let you make code automatically from a file, which is the same as extending C.

  • Open-source

Since C is an open-source programming language, any programmer can change the source code and use it however they want. Programmers can also share with libraries that meet their needs when they use C. It can make every part of how C programs are put together better.

  • Words to use when making structured programs

Since C is a structured programming language, each code block must start and end with a pair of braces. The programmer can use these brackets to make it easier for the end user to read the code inside each function.

  • Standard language usage

C can be used for low-level and high-level development as a middle-level language. It’s a good choice because it’s valuable and easy to carry.

  • Implementation of algorithms and data structures

When you want to write code for algorithms and data structures, C is a great language to use. Even though C seems simple, it has been used to make some of the most important and influential software, like operating systems, compilers, debuggers, and more.

  • Procedural programming language

C is a procedural programming language that tells the computer what to do in a specific order. It is called “procedural” because it uses functions and procedures already set up to handle everyday tasks like input/output. C lets you use inheritance, polymorphism, encapsulation, all parts of object-oriented programming. Programmers can write code that can be used more than once with C.

  • Dynamic memory allocation

The C programming language has a “dynamic memory allocation” feature, which lets you give and take memory segments on the fly. There’s no way to know exactly how much storage space you’ll need, so this feature is a must in programming languages today.

You Must Know: Top Java Programs asked in Interviews to Beginners and Experienced

What Are C Programming Interview Questions?

Of course, almost all of the world’s largest multinational corporations conduct job interviews using C Programming interview questions based on the C programming language (MNCs). This article discusses the most popular C programming interview questions that have emerged over the past few years due to their widespread use. C Programming Interview Questions and Answers are also provided for users of all experience levels, ranging from novices to seasoned pros.

C Programming Basic Interview Questions and Answers for Freshers

Here are some possible C programming interview questions for Freshers and how to answer them.

1. C’s “I” and “i++” operators look much alike. What makes them different?

The pre-increment operator, written as I, raises the value of I before the expression uses it. With “i++,” the post-increment operator, the value of I goes up after it has been used in a word.

2. So, what does a pointer mean in C?

Another variable can track one variable’s location in memory via a pointer. In a roundabout approach, you can access the variable the information points to and alter its value using the pointer.

3. What is the difference between a pointer and an array in the C language?

One type of variable is known as a pointer, and its purpose is to store the memory address of another variable. The collection of variables of the exact same data type is known as an array.

When working with arrays in C, a pointer to the first item in the collection and the display itself may be the same.

4. What’s the difference between a C union and a C structure?

A union block can have several instances of the same value, in contrast to a structure, which can only store a single example of a given type’s value. This is what differentiates a union from a system. While unions conserve memory by keeping many data types in the exact location, structures are used to hold data connected.

5. Explain a function pointer and how it works in C.

The memory address of a function can be stored in a function pointer, which operates similarly to a variable. It is possible to pass it along to another position to be used as an argument or to utilize it to call the process in a roundabout way.

6. Which is better in C: “malloc” or “calloc,” and why?

We use the “calloc” function to give an array memory and set its first value to zero.

The contents of a single block of memory given by “malloc” are not set up.

7. What does “const” mean in the language C?

Using the “const” keyword, you can make a variable read-only, meaning it cannot change its value after it has been set.

8. What does “volatile” mean in the language C?

The “volatile” keyword shows that a variable’s value could change outside the application’s scope. If you use this keyword, the compiler won’t be able to improve the variable’s value.

9. What are the most fundamental datatypes that can use in C?

Ans: There are four main groups of datatypes in the C programming language. Here are some of them:

  • Basic Datatypes
  • Derived Datatypes
  • Enumerated Datatypes
  • Void Datatypes

10. Make a difference between “real world” and “formal” parameters.

Actual parameters are the ones that are passed from the primary function to the delegated function. Formal parameters are the ones that are listed at the end of the trusted process.

C Programming Tricky Questions

Here are some tricky C Programming questions with answers:

1. Explain the difference between the > and the ” ” when a header file is declared.

The compiler will default look for a header file in the current working directory. If you use > to define it, it will look at the system’s Built-in Path instead. The compiler will look for the declared Header File in the current working directory. If it isn’t there, it will look like other guides.

2. At what point should we tell the computer to store registers?

Through a Register Storage Specifier, we can inform the computer of the location at which it should keep a frequently accessed variable. Since this will define the variable in a CPU register, it is straightforward for the compiler to locate it.

3. Can you explain what it means to “typecast” someone?

Typecasting is the process of changing one type of data into another. If we want to save the value in an int variable, we must do an explicit conversion from the floating-point number type to the integer number type.

4. Which C storage class specifiers are there?

Ans: Here are the different storage specifiers you can use in the C language:

  • Auto
  • Register
  • Static
  • Extern

5. What does it mean to be typecast?

Typecasting is the process of changing one type of data into another. If we store the value of a floating type in an int type, we will explicitly change the data type into another data type.


1 (type_name) expression;

6. Write a code to print the following pattern.






7. Which framework connects the program to the operating system?

The following will give you more information:

The term “file” refers to the structure that connects an operating system (OS) and a piece of software (software).

The stdio defines the file.h file, which is a standard input/output header file.

The size of the file, where it is in memory, and other information about the currently open file are all written here.

There is also a character pointer that tells where the opened character is.

When a file is opened, the program and operating system connect so that the software knows exactly how to get to the file.

8. What does scanf() not do, and how can it be avoided?

Ans: Here are some of scanf(limitations: )’s

C programming cannot use the string of characters with scanf().

Using scanf, you can’t put a string with more than one word into a single variable ().

The gets() function is used to avoid this.

It takes a string from the keyboard and ends when the enter key is hit.

In this case, the spaces and tabs can be part of the input string.

9. You need to tell the difference between functions and macros.

The difference between macros and functions can be seen in c programming in the following ways:

The bigger versions of the templates replace the smaller ones when a macro is run.

But the faster execution time is lost because the Macro call makes the whole program more significant.Compared to other ways to avoid function call mistakes, the Macro is easy to use and works well. The process’s control and parameters are sent simultaneously when a function is called. It makes them easier to use and smaller.

Hurt the program’s performance by the time it took to pass arguments and get the value returned.

10. Let’s say that the name of a global variable and a local variable is the same. Can a local variable be accessed from a block defined by a global variable?

Ans: No. It can’t happen in C. The most crucial variable is always the one that is closest to us.

Examples of C Programming Coding Questions:

Here are some examples of c programming coding questions that could ask at an interview for a C programmer:

  1. Write a program that can figure out the factorial of a number.
  2. Make some code that adds up all the numbers in an array.
  3. Write some code to sort an array of integers from smallest to largest.
  4. Create an algorithm that can reverse a string.
  5. Coding a check to see if a line is a palindrome is challenging but rewarding.
  6. Write some code to add up the digits of a number.
  7. Write some code to determine which values in an array are the most and least important.
  8. Make a program that can count the number of times a character appears in a string.
  9. Write a program that can tell if a given number is prime.
  10. Make an algorithm to find the exponent of a number.

These are some of the different kinds of C programming interview questions that could ask. The difficulty level of the questions will depend on the job and the candidate’s experience level.


In the digital world we live now, C programming is still a crucial part of making software. C programming is still functional, even though newer languages have come out recently. It is used in many places, like operating systems, embedded systems, scientific computing, games, etc.

Many businesses use C programming because it makes good use of system resources and can be used for low-level programming. The need for C programming skills has grown as the Internet of Things (IoT), and embedded systems have become more popular.

Companies can benefit from using C-programming interview questions because they let them test potential new hires’ technical knowledge and how well they know C. Potential employers may ask questions about data structures, algorithms, memory management, and system programming to see if a candidate can write code that works well and is well-structured. By asking these questions, hiring managers can determine if candidates can write code that meets their needs. Employers can find out how good a candidate is at looking at problems and coming up with reasonable solutions by asking them C Programming coding questions at different points in the interview process. C programming interview questions are a good way for potential employers to see how qualified candidates are for a job and ensure they hire the best person.

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