Top 20 C Programming Language Interview Questions and Answers

C was originally developed by Dennis Ritchie between 1969 and 1973 at AT&T Bell Labs, and used to (re-)implement the Unix operating system. 

It has since become one of the most widely used programming languages of all time, with C compilers from various vendors available for the majority of existing computer architectures and operating systems. 

C has been standardized by the American National Standards Institute (ANSI) since 1989 (see ANSI C) and subsequently by the International Organization for Standardization (ISO).

Top 20 C Programming Language Interview Questions and Answers for freshers and experienced are Below

1. Founder of C Language?

Dennis Ritchie

2. C initially developed from?

Derived from the typeless language BCPL,

3. feature of c language?

Low Level Features

Portability

Powerful

Bit Manipulation

High Level Features

Modular Programming

Efficient Use of Pointers

More Efficient

4. Application Of C Programming?

C Programming Language called as Middle level Programming Language. C Programming can be used to do verity of tasks such as networking related,OS related.

Application of C Programming are listed below -

• Creating computer applications 
• Used in writing Embedded softwares
• Firmware for various electronics, industrial and communications products which use micro-controllers.
• It is also used in developing verification software, test code, simulators etc. for various applications and hardware products.
• For Creating Compiles of different Languages which can take input from other language and convert it into lower level machine dependent language.
• C is used to implement different Operating System Operations.
• UNIX kernel is completely developed in C Language.

5. Write a Simple C Program.

//C hello world example

#include <stdio.h>

int main()

{

  printf("Hello world\n");

  return 0;

}

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6. Why use C?

C has been used successfully for every type of programming problem imaginable from operating systems to spreadsheets to expert systems - and efficient compilers are available for machines ranging in power from the Apple Macintosh to the Cray supercomputers. 

The largest measure of C's success seems to be based on purely practical considerations:

• the portability of the compiler;
• the standard library concept;
• a powerful and varied repertoire of operators;
• an elegant syntax;
• ready access to the hardware when needed;
• and the ease with which applications can be optimised by hand-coding isolated procedures

7. Uses of C?

• Operating Systems
• Language Compilers
• Assemblers
• Text Editors
• Print Spoolers
• Network Drivers
• Modern Programs
• Data Bases
• Language Interpreters
• Utilities

8. Structure of C Programs?

Having completed this section you should know about:

• C's character set
• C's keywords
• the general structure of a C program
• that all C statement must end in a ;
• that C is a free format language
• all C programs us header files that contain standard library functions.

9. Data Types of C?

There are five basic data types associated with variables:

• int - integer: a whole number.
• float - floating point value: ie a number with a fractional part.
• double - a double-precision floating point value.
• char - a single character.
• void - valueless special purpose type which we will examine closely in later sections.

10. Input and Output Functions?

• input functions, called scanf
• output functions, called printf

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11. What is Pointer?
a variable whose value is the address of another variable

12. Syntax error?

a syntax error is an error in the syntax of a sequence of characters or tokens that is intended to be written in a particular programming language.

For compiled languages syntax errors occur strictly at compile-time. A program will not compile until all syntax errors are corrected.

13. What is debugging?

Debugging is the process of locating and fixing or bypassing bugs (errors) in computer program code or the engineering of a hardware device.

14. What are reserved words?

a word in a programming language which has a fixed meaning and cannot be redefined by the programmer.

15. What is loop?

A loop describes the process of a software program or script repeats the same instructions or processes the same information over and over until receiving the order to stop. 

If not handled properly a loop can cause the computer to become slower as it becomes overwhelmed with having to repeat the same steps over and over causing it to get stuck in an endless loop. Below is a basic example of a loop in a batch file.