C Interview Questions and Answers

Last updated on Feb 10, 2022
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C Interview Questions

C is a robust, powerful and fast general-purpose programming language. For fresher developers, C can be an excellent choice to start their programming journey. If you are preparing for the C language job interview, we have one of the biggest collection of C Interview Questions.

It is portable and available on all platforms. A lot of programming language such as PHP, Java, and JavaScript that made their entry after the C language has directly or indirectly borrowed features and syntax /features from it. C++ language is almost an extension of the C language. A lot of recent C programming interview questions were based on this information.

Our unique extensively researched C language interview questions are the best way to prepare for job interviews.

C Language
What is C language? C is a general-purpose, procedural computer programming language supporting structured programming, lexical variable scope, and recursion, whilst a static kind machine prevents unintended operations.
Latest Version C18 and released in June 2018
Developed By Dennis Ritchie & Bell Labs
Designed By Dennis Ritchie

Most Frequently Asked C Interview Questions

Here in this article, we will be listing frequently asked C Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. How is a NULL pointer different from a Dangling pointer?
S.no NULL Pointer Dangling pointer
1. Indicates the pointer isn't pointing to a valid location Does not point to a correct place
2. Happens when memory pointed by it is deallocated Occurs when an object is removed or deleted
Q2. What are local static variables? How can you use them?

A local static variable gets defined in a specific block and is accessible locally inside that block only. However, because it is static, its value is persistent. Its lifetime does not end when a function call is declared. Instead, its lifetime extends throughout the program. Local static variables can be used for counting the number of times a particular function is called.

Q3. Differentiate abs() function from fabs() function.
S.no abs() fabs()
1. Used for integer values Used only for floating type
2. Prototype is under < stdlib.h > Prototype is under < math.h >
3. Returns absolute value of integer Returns absolute value of a floating-point
Q4. How is = symbol different from == symbol in C programming?
S.no “=” “==”
1. Assignment operator Comparison operator
2. Used to assign the value of right side to the variable on the left side Used to compare value on the left side with value on the right side
Q5. Why are algorithms important in C program?

It is a mandatory step to create an algorithm before writing any program in C. An algorithm gives step-by-step guidelines on how a solution can be achieved and also serves as a blueprint on how a program should start or end, including what processes and computations must be involved.

Q6. How is actual parameter different from the formal parameter?
S.no Actual Parameters Formal Parameters
1. Used in the function call Used in the function header
2. Pass actual values to the function definition Receive values passed to function
3. Can be constant or variable Treated as local variables
Q7. Why is C called "mother" language?

C is often referred to as the mother of all programming language because it is one of the most popular programming languages. Right from the time, it was developed, C has become the most widely used and preferred programming languages. Most of the compilers and kernels are written in C today.

Q8. What is an array? What the different types of arrays in C?

An Array is a group of elements having similar data types under a common name. In an array, the two-dimensional elements are stored in rows as per the memory locations. An element's array name represents the address of that element. It must be noted that the size of size is always constant and never a variable.

In C language, there are two types of arrays - Single Dimensional Array and Multi-Dimensional Array.

Q9. What do you mean by dynamic memory allocation in C? What functions are used?

It refers to the mechanism by which storage or memory gets allocated dynamically to variables during the runtime. This mechanism uses malloc(), and calloc() functions to allocate memory dynamically.

free() function is used to release dynamically allocated memory.

Q10. Compare interpreters and compilers.
S.no Interpreters Compilers
1. Deal with the way code gets executed Check the syntax of the program
2. Executes programs written in a source language Converts source language into object language.
3. Converts one line at a time Converts entire program in one time

C is a robust language with a rich set of built-in features and functions that can be used to build any complex web program. The C compiler has the potential of an assembly language and functionalities of a high-end language. The programs written in this language are robust and efficient, mainly due to its unique data type and strong operators. Much faster than BASIC, it is one of the most widely used languages in OS and embedded system development. On our website, we have provided potential C interview questions.

As a programming language, C is one of the best languages known due to its simplicity of syntax coupled with fantastic functionality. Despite being 40 years old, C language is still trendy. One of the biggest reasons is that the source code written in C works in another OS without a single change. This language is a perfect mix of ease of use with robust features, which makes it an ideal language to be taught to even fresher developers, with an aim to introduce the programming world to them. We can help you prepare for C Interview Questions and Answers by educating you in-depth about this language.

Development History

Initially developed during around 1972 - 1973 at Bell Labs by Dennis Ritchie, mainly for writing OS like UNIX. Some people call it a successor of the B language that was written in the early 1970s. This information is mostly asked during C interview questions.

Latest Version

Many candidates were asked about the features in the latest versions during about their C Programming Interview Questions. C18‎ is the latest stable version, which was released on June 2018.

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