C language is one of the most complete programming software with more advantages instead of disadvantages, this language has an infinitive kind of uses, the possibility of questions is infinitive too. If you have been considered for a C interview, you must take care of your preparation.


C Programming Interview Questions With Answers

There are several techniques and tips that you must know before an interview. We recommend obtain all the possible information about the company, a good way to start is on the web and if you have some friend that is working in the same company it is advisable to ask him for information.

The next step is the preparation, C interview questions sometimes are very difficult, and the level of difficulty will depend about the company and what they do, most people forget or don’t give enough time to the preparation.

C interview questions are a type of test with complicated questions and directly related to the company or the job that you are applying. There is not a set format of questions, but the most probable questions that are going to be taken from your resume. By the way, there are several common questions that could be taken.

In the next information, we have listed the most common questions and answers classified into 3 themes:

  1. Variables & Control Flow
  2. Operators, constants and structures
  3. Functions

Variables & Control Flow

It is referred with different variables and control flow statements such as if-else statements, loop statements, for, while and even more, In this section you will find the most possible and common questions that could be considered in an interview.

What is the difference between declaring a variable and defining a variable?
Declaration of a variable in C hints the compiler about the type and size of the variable in compile time. Similarly, declaration of a function hints about the type and size of function parameters. No space is reserved in memory for any variable just in case of a declaration.

What is a static variable?
Astatic variables may be a special variable that’s stored within the data segment, unlike the default automatic variable that’s stored in the stack. A static variable is often initialized by using keyword static before the variable name.
What is a register variable?
Register variables are stored in the CPU registers. It’s default value is a garbage value. The scope of a register variable is local to the block during which it’s defined. Lifetime is until control remains within the block during which the register variable is defined.

Where is an auto variables stored?
Main memory and CPU registers are the 2 memory locations where auto variables are stored. Auto variables are defined under automatic storage class. They are stored in the main memory. Memory is allocated to an automatic variable when the block which contains it’s called and it’s de-allocated at the completion of its block execution.

Auto variables:

Storage: main memory.
Default value:garbage value.
Scope:local to the block during which the variable is defined.
Lifetime:till the control remains within the block during which the variable is defined.

C Programming Interview Questions With Answers

Operators, constants and structures

In all types of languages are used, the variables and the constants are used to save data, the structures are used to control the flow of the software and the structures are used to generate the repetition of the instruction. The next questions and answers listed are going to be helpful.

What are the advantages of using unions?
The union may be a collection of knowledge items of various data types. It can hold data of just one member at a time though it’s members of various data types. If a union has two members of different data types, they’re allocated an equivalent memory. The memory allocated is adequate to the maximum size of the members. The data is interpreted in bytes counting on which member is being accessed.

What means the structure If-Then-Else?
This structure means a condition, to run or not execute a particular task or line of code.

What means the structure while-wend?
his control structure will repeat without stopping certain code while the condition is met.

How can typedef be to define a type of structure?
typedef declaration helps to make source code of a C program more readable. Its purpose is to redefine the name of an existing variable type. It provides a brief and meaningful thanks to call a knowledge type. typedef is beneficial when the name of the info type is long. Use of typedef can reduce length and complexity of knowledge types.


In C every programming language has an equivalent of a function, using a function we can create a big structure. Please review all the possible information about functions.

What is the purpose of main() function?
In C, program execution starts from the main() function. Every C program must contain a main() function. The main function may contain any number of statements. These statements are executed sequentially within the order which they’re written.

What is recursion? Write a program using recursion (factorial)?
Recursion: A function is named ‘recursive’ if a press release within the body of a function calls an equivalent function. It is also called ‘circular definition’. Recursion is thus a process of defining something in terms of itself.

Explain command line arguments of main function?
In C, we will supply arguments to ‘main’ function. The arguments that we pass to main ( ) at prompt are called instruction arguments. These arguments are supplied at the time of invoking the program.

The main ( ) function can take arguments as: main(intargc, char *argv[]) { }

The first argument argc is understood as ‘argument counter’. It represents the number of arguments within the instruction. The second argument argv is understood as ‘argument vector’. It is an array of char type pointers that points to the instruction arguments. Size of this array are going to be adequate to the worth of argc.

This is just a bit of the large possible questions, Review information about pointers and programs in C.

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