Techalert

Top 20 C Programming Language Interview Questions and Answers

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: left;">
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. </div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
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. </div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1-ZhbOslXCoZJEEht3vEGEdyadFuLVV3RErZSfiaPWzZBM_fl9QXpprrwzUVBg_7qM6babLdzAo6SM2c958jbkkN_drTHN_aeOlaiqiZQKQJnaEBWwStwAIXK9hAr9FGPnfwCrOOQuA/s1600/c-interview.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt=" C Language Interview QA" border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1-ZhbOslXCoZJEEht3vEGEdyadFuLVV3RErZSfiaPWzZBM_fl9QXpprrwzUVBg_7qM6babLdzAo6SM2c958jbkkN_drTHN_aeOlaiqiZQKQJnaEBWwStwAIXK9hAr9FGPnfwCrOOQuA/s1600/c-interview.jpg" title=" C Language Interview QA" width="550" /></a></div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
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).</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<h3 style="clear: both; text-align: left;">
<b>Top 20 <span style="color: #6aa84f;">C Programming Language Interview Questions and Answers</span> </b>for freshers and experienced are Below</h3>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
<b>1. Founder of C Language?</b></div>
<div class="separator" style="clear: both; text-align: left;">
Dennis Ritchie</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
<b>2. C initially developed from?</b></div>
<div class="separator" style="clear: both;">
Derived from the typeless language BCPL,</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
<b>3. feature of c language?</b></div>
<div class="separator" style="clear: both;">
Low Level Features</div>
<div class="separator" style="clear: both;">
Portability</div>
<div class="separator" style="clear: both;">
Powerful</div>
<div class="separator" style="clear: both;">
Bit Manipulation</div>
<div class="separator" style="clear: both;">
High Level Features</div>
<div class="separator" style="clear: both;">
Modular Programming</div>
<div class="separator" style="clear: both;">
Efficient Use of Pointers</div>
<div class="separator" style="clear: both;">
More Efficient</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
<b>4. Application Of C Programming?</b></div>
<div class="separator" style="clear: both;">
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.</div>
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
Application of C Programming are listed below -</div>
<div class="separator" style="clear: both; text-align: left;">
</div>
<ul style="text-align: left;">
<li>Creating computer applications </li>
<li>Used in writing Embedded softwares</li>
<li>Firmware for various electronics, industrial and communications products which use micro-controllers.</li>
<li>It is also used in developing verification software, test code, simulators etc. for various applications and hardware products.</li>
<li>For Creating Compiles of different Languages which can take input from other language and convert it into lower level machine dependent language.</li>
<li>C is used to implement different Operating System Operations.</li>
<li>UNIX kernel is completely developed in C Language.</li>
</ul>
<br />
<div class="separator" style="clear: both; text-align: left;">
<b>5. Write a Simple C Program.</b></div>
<div class="separator" style="clear: both;">
//C hello world example</div>
<div class="separator" style="clear: both;">
#include <stdio.h></div>
<div class="separator" style="clear: both;">
int main()</div>
<div class="separator" style="clear: both;">
{</div>
<div class="separator" style="clear: both;">
  printf("Hello world\n");</div>
<div class="separator" style="clear: both;">
  return 0;</div>
<div class="separator" style="clear: both;">
}</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div style="text-align: center;">
<span style="background-color: white; color: #333333; font-family: "verdana" , "geneva" , sans-serif; font-size: 12px; line-height: 19.200000762939453px;"></span><b style="background-color: white; color: #333333; font-family: Verdana, Geneva, sans-serif; font-size: 12px; line-height: 19.200000762939453px;"><span style="color: #990000;">Also Read:</span> <a href="http://www.itechaleart.com/2014/04/top-50-common-interview-qa.html" style="color: #999999; text-decoration: none;"><span style="color: #3d85c6;">Top 50 Common Job Interview Questions and answers</span></a></b></div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
<b>6. Why use C?</b></div>
<div class="separator" style="clear: both; text-align: left;">
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. </div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
The largest measure of C's success seems to be based on purely practical considerations:</div>
<div class="separator" style="clear: both;">
</div>
<ul style="text-align: left;">
<li>the portability of the compiler;</li>
<li>the standard library concept;</li>
<li>a powerful and varied repertoire of operators;</li>
<li>an elegant syntax;</li>
<li>ready access to the hardware when needed;</li>
<li>and the ease with which applications can be optimised by hand-coding isolated procedures</li>
</ul>
<b>7. Uses of C?</b><br />
<div class="separator" style="clear: both;">
</div>
<ul style="text-align: left;">
<li>Operating Systems</li>
<li>Language Compilers</li>
<li>Assemblers</li>
<li>Text Editors</li>
<li>Print Spoolers</li>
<li>Network Drivers</li>
<li>Modern Programs</li>
<li>Data Bases</li>
<li>Language Interpreters</li>
<li>Utilities</li>
</ul>
<b>8. Structure of C Programs?</b><br />
<div class="separator" style="clear: both;">
Having completed this section you should know about:</div>
<div class="separator" style="clear: both;">
</div>
<ul style="text-align: left;">
<li>C's character set</li>
<li>C's keywords</li>
<li>the general structure of a C program</li>
<li>that all C statement must end in a ;</li>
<li>that C is a free format language</li>
<li>all C programs us header files that contain standard library functions.</li>
</ul>
<div class="separator" style="clear: both;">
<b>9. Data Types of C?</b></div>
<div class="separator" style="clear: both;">
There are five basic data types associated with variables:</div>
<div class="separator" style="clear: both;">
</div>
<ul style="text-align: left;">
<li>int - integer: a whole number.</li>
<li>float - floating point value: ie a number with a fractional part.</li>
<li>double - a double-precision floating point value.</li>
<li>char - a single character.</li>
<li>void - valueless special purpose type which we will examine closely in later sections.</li>
</ul>
<div class="separator" style="clear: both;">
<b>10. Input and Output Functions?</b></div>
<div class="separator" style="clear: both;">
</div>
<ul style="text-align: left;">
<li>input functions, called scanf</li>
<li>output functions, called printf</li>
</ul>
<div style="text-align: center;">
<b style="background-color: white; color: #777777; font-family: Verdana, Geneva, sans-serif; font-size: 12px; line-height: 24px;"><span style="color: #990000;">Also Read:</span> <a href="http://www.itechaleart.com/2014/04/seo-interview-qa.html" style="color: #999999; text-decoration: none;" target="_blank"><span style="color: #3d85c6;">Top 25 SEO Interview Questions and Answers</span></a></b></div>
<div>
<br /></div>
<b>11. What is Pointer?</b><br />
a variable whose value is the address of another variable<br />
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
<b>12. Syntax error?</b></div>
<div class="separator" style="clear: both;">
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.</div>
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
</div>
<div class="separator" style="clear: both;">
For compiled languages syntax errors occur strictly at compile-time. A program will not compile until all syntax errors are corrected.</div>
<div class="separator" style="clear: both;">
<b><br /></b></div>
<div class="separator" style="clear: both;">
<b>13. What is debugging?</b></div>
<div class="separator" style="clear: both;">
Debugging is the process of locating and fixing or bypassing bugs (errors) in computer program code or the engineering of a hardware device.</div>
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
<b>14. What are reserved words?</b></div>
<div class="separator" style="clear: both;">
a word in a programming language which has a fixed meaning and cannot be redefined by the programmer.</div>
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
<b>15. What is loop?</b></div>
<div class="separator" style="clear: both;">
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. </div>
<div class="separator" style="clear: both;">
<br /></div>
<div class="separator" style="clear: both;">
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.</div>
</div>

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 ...

Top C Programming Language Interview Questions and Answers

<div dir="ltr" style="text-align: left;" trbidi="on">
<div>
</div>
<div>
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi61Sdw7XXIcXGkD_zA2XzzPvsgdfDeoUrAtHbKmUCjZBFWH7TcU7AU6U17cccIn5q7XXHlAWFFKkYzMTcoMNfKMLPNATtsXumd1tOD1W27IFReRhE1B0apL9GkK_ERIy29PxlFj-DeUQ/s1600/c-interview.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="C Language interview QA" border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi61Sdw7XXIcXGkD_zA2XzzPvsgdfDeoUrAtHbKmUCjZBFWH7TcU7AU6U17cccIn5q7XXHlAWFFKkYzMTcoMNfKMLPNATtsXumd1tOD1W27IFReRhE1B0apL9GkK_ERIy29PxlFj-DeUQ/s1600/c-interview.jpg" title="C Language interview QA" width="550" /></a></div>
<div>
<br /></div>
<div>
<div>
<h3 style="text-align: left;">
<span style="color: #6aa84f;">List of Top C Programming Language Interview Questions and Answers for freshers and experienced are below:</span></h3>
</div>
<br />
<b>1) Who invented <span style="color: #3d85c6;">C Language</span>?</b><br />
-->  Dennis Ritchie in 1972 developed a new language by inheriting the features of both BCPL and B and adding additional features. He named the language as just C.<br />
<br />
<b>2) Who invented B Language?</b><br />
-->  Ken Thomson at AT&T Bell Labs developed a language and named it B. Even the B language was found to have some short comings to support development of both business applications and system software.<br />
<br />
<b>3) Who invented BCPL Language?</b><br />
-->  Basic Combined Programming Language(BCPL) was developed by Martin Richards, Cambridge university.<br />
<br />
<b>4) Why C Language?</b><br />
-->  C is one of the high level languages. It is a general purpose language, which means it can be used to write programs of any sort.<br />
<br />
<b>5) What are the <span style="color: #3d85c6;">features of C</span> Langauges?</b><br />
=> In C one can write programs like that of high level languages as in COBOL, BASIC, FORTRAN etc. as well as it permits very close interaction with the inner workings of the computer.<br />
=> It is a general purpose programming language. It is usually called system programming language but equally suited to writing a variety of applications.<br />
=> It supports various data types<br />
=> It follows the programming style based on fundamental control flow constructions for structured programming<br />
=> Functions may be predefined or user defined and they may return values of basic types, structures, unions or pointers.<br />
<br />
<div style="text-align: center;">
<b style="background-color: white; color: #333333; font-family: Verdana, Geneva, sans-serif; font-size: 12px; line-height: 19.200000762939453px;"><span style="color: #990000;">Also Read:</span> <a href="http://www.itechaleart.com/2014/04/top-50-common-interview-qa.html" style="color: #999999; text-decoration: none;"><span style="color: #3d85c6;">Top 50 Common Job Interview Questions and answers</span></a></b></div>
<br />
<div>
<b>6)What are the <span style="color: #3d85c6;">advantages of c</span> language?</b><br />
=> Easy to write<br />
=> Rich set of operators and functions that are built–in<br />
=> Support for bit–wise operation<br />
=> Flexible use of pointers<br />
=> Direct control over the hardware<br />
=> Ability to access BIOS/DOS routines<br />
=> Interacting using Interrupts<br />
=> Ability to write TSR programs<br />
=> Ability to create .COM files<br />
=> Ability to create library files (.LIB)<br />
=> Ability to write interface programs<br />
=> Incorporating assembly language in C program<br />
<br />
<b>7) What are the disadvantages of c language?</b><br />
=> C is considered difficult to learn<br />
=> Because of its conciseness, the code can be difficult to follow<br />
=> It is not suited to applications that require a lot of report formatting and data file manipulation<br />
<br />
<b>8) What are the salient features of c languages?</b><br />
=> The following are the salient features of C language are :<br />
=> C is called a middle level language<br />
=> C supports structured design approach<br />
=> C is extensible<br />
=> C is rich in data types and operators<br />
=> C is portable<br />
<br />
<b>9) What is a <span style="color: #3d85c6;">header file</span>?</b><br />
-->  Header files provide the definitions and declarations for the library functions. Thus, each header file contains the library functions along with the necessary definitions and declarations. For example, stdio.h, math.h, stdlib.h, string.h etc.<br />
<br />
<b>10) What is character set?</b><br />
-->  Character set is the set of characters allowed and supported in the programming language.</div>
<div>
<br /></div>
<div>
Generally a program is a collection of instructions, which contain groups of characters. Only a limited set of characters is allowed to write instructions in the program.<br />
<br />
<div style="text-align: center;">
<b style="background-color: white; color: #333333; font-family: Verdana, Geneva, sans-serif; font-size: 12px; line-height: 19.200000762939453px;"><span style="color: #990000;">Also Read:</span> <a href="http://www.itechaleart.com/2013/06/top-50-oop-interview-questions.html" style="color: #999999; text-decoration: none;"><span style="color: #3d85c6;">Top 50 OOPs Interview Questions and Answers</span></a></b></div>
<br />
<b>11) What is C token?</b><br />
-->  The smallest individual units of a C program are known as tokens.<br />
<br />
<b>12) List the different types of <span style="color: #3d85c6;">C tokens</span>?</b><br />
=> Constants<br />
=> Identifiers<br />
=> Keywords<br />
=> Operators<br />
=> Special symbols<br />
=> Strings<br />
<br />
<b>13) What is a <span style="color: #3d85c6;">string</span>?</b><br />
-->  A string is a sequence of characters ending with NUL. It can be treated as a one–dimensional array of characters terminated by a NUL character.<br />
<br />
<b>14) What are qualifiers?</b><br />
-->  Qualifiers or modifiers are identifiers that may precede the scalar data types (except float) to specify the number of bits used for representing the respective type of data in memory. The qualifiers in C are short, long, signed, and unsigned.<br />
<br />
<b>15) What is a <span style="color: #3d85c6;">function</span>?</b><br />
-->  A function is a set of statements to perform a specific task.<br />
<br />
<b>16) What is a <span style="color: #3d85c6;">constant</span>?</b><br />
-->  A constant is a value that does not change during the program execution. A constant used in C does not occupy memory.<br />
<br />
<b>17) What are the different types of constants?</b><br />
=> There are five types of constants. They are :<br />
=> Integer constants<br />
=> Floating point constants<br />
=> Character constants<br />
=> String literals<br />
=> Enumeration constants<br />
<br />
<b>18) What is <span style="color: #3d85c6;">variable</span>?</b><br />
-->  An identifier is used to identify and store some value. If the value of the identifier is changed during the execution of the program, then the identifier is known as variable.<br />
<br />
<b>19) What are the rules for the <span style="color: #3d85c6;">identifier</span>?</b><br />
=> The first character must be an alphabet or underscore (_)<br />
=> Digits may be included in the variable<br />
=> The maximum number of characters in a word are 32 (It may vary depending upon the platform)<br />
=> No other special characters are allowed.<br />
<br />
<b>20) What are <span style="color: #3d85c6;">global variables</span>?</b><br />
-->  Global Variables are those, which are required to be acccessed by all the functions defined after their declaration. So, the variables declared before the main {) can be acccessed by all the functions, which follow their declaration.<br />
<br />
<b>21) What is the purpose of main( ) function? </b><br />
-->  The function main( ) invokes other functions within it.It is the first function to be called when the program starts execution.<br />
- It is the starting function<br />
- It returns an int value to the environment that called the program<br />
- Recursive call is allowed for main( ) also.<br />
- It is a user-defined function<br />
- Program execution ends when the closing brace of the function main( ) is reached.<br />
- It has two arguments 1)argument count and 2) argument vector (represents strings passed).<br />
- Any user-defined name can also be used as parameters for main( ) instead of argc and argv<br />
<br />
<b>22) Why n++ executes faster than n+1? </b><br />
-->  The expression n++ requires a single machine instruction such as INR to carry out the increment operation whereas, n+1 requires more instructions to carry out this operation.<br />
<br />
<b>23) What will the <span style="color: #3d85c6;">preprocessor </span>do for a program? </b><br />
-->  The C preprocessor is used to modify your program according to the preprocessor directives in your source code. A preprocessor directive is a statement (such as #define) that gives the preprocessor specific instructions on how to modify your source code.<br />
<br />
The preprocessor is invoked as the first part of your compiler program’s compilation step. It is usually hidden from the programmer because it is run automatically by the compiler. <br />
<br />
The preprocessor reads in all of your include files and the source code you are compiling and creates a preprocessed version of your source code. This preprocessed version has all of its macros and constant symbols replaced by their corresponding code and value assignments.<br />
<br />
If your source code contains any conditional preprocessor directives (such as #if), the preprocessor evaluates the condition and modifies your source code accordingly.<br />
<br />
<b>24) What is the benefit of using const for declaring constants? </b><br />
-->  The benefit of using the const keyword is that the compiler might be able to make optimizations based on the knowledge that the value of the variable will not change. In addition, the compiler will try to ensure that the values won’t be changed inadvertently. Of course, the same benefits apply to #defined constants.<br />
<br />
The reason to use const rather than #define to define a constant is that a const variable can be of any type (such as a struct, which can’t be represented by a #defined constant). Also, because a const variable is a real variable, it has an address that can be used, if needed, and it resides in only one place in memory<br />
<br />
<b>25) Is it better to use a macro or a function? </b><br />
-->  The answer depends on the situation you are writing code for. Macros have the distinct advantage of being more efficient (and faster) than functions, because their corresponding code is inserted directly into your source code at the point where the macro is called.<br />
<br />
There is no overhead involved in using a macro like there is in placing a call to a function. However, macros are generally small and cannot handle large, complex coding constructs. A function is more suited for this type of situation. Additionally, macros are expanded inline, which means that the code is replicated for each occurrence of a macro. Your code therefore could be somewhat larger when you use macros than if you were to use functions. <br />
<br />
Thus, the choice between using a macro and using a function is one of deciding between the tradeoff of faster program speed versus smaller program size. Generally, you should use macros to replace small, repeatable code sections, and you should use functions for larger coding tasks that might require several lines of code.<br />
<br />
<b>26) What are the standard predefined macros? </b><br />
-->  The ANSI C standard defines six predefined macros for use in the C language:<br />
<br />
<span style="color: #3d85c6;">Macro Name Purpose::</span><br />
_ _LINE_ _ Inserts the current source code line number in your code. <br />
_ _FILE_ _ Inserts the current source code filename in your code. <br />
_ _ Inserts the current date of compilation in your code. <br />
_ _TIME_ _ Inserts the current time of compilation in your code. <br />
_ _STDC_ _ Is set to 1 if you are enforcing strict ANSI C conformity. <br />
_ _cplusplus Is defined if you are compiling a C++ program.</div>
</div>
</div>

Top C Programming Language Interview Questions and Answers

List of Top C Programming Language Interview Questions and Answers for freshers and experienced are below: 1) Who invented C ...