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TOP 100INTERVIEW QUESTIONS & ANSWERS
C
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Who invented C Language?
2
QUESTION
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
ANSWER
QUESTION 1
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What are the features of C Langauges?
3
QUESTION
• 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.
• It is a general purpose programming language. It is usually called system programming language but equally
suited to writing a variety of applications.
• It supports various data types
• It follows the programming style based on fundamental control flow constructions for structured programming
• Functions may be pre–defined or user defined and they may return values of basic types, structures, unions or
pointers
ANSWER
QUESTION 2
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What are the advantages of c language?
4
QUESTION
• Easy to write
• Rich set of operators and functions that are built–in
• Support for bit–wise operation
• Flexible use of pointers
• Direct control over the hardware
• Ability to access BIOS/DOS routines
• Interacting using Interrupts
• Ability to write TSR programs
• Ability to create .COM files
• Ability to create library files (.LIB)
• Ability to write interface programs
• Incorporating assembly language in C program
ANSWER
QUESTION 3
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What is a header file?
5
QUESTION
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.
ANSWER
QUESTION 4
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List the different types of C tokens?
6
QUESTION
• Constants
• Identifiers
• Keywords
• Operators
• Special symbols
• Strings
ANSWER
QUESTION 5
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What is a constant? What are the different types of constants?
7
QUESTION
A constant is a value that does not change during the program execution. A constant used in C does not occupy
memory. There are five types of constants. They are:
• Integer constants
• Floating point constants
• Character constants
• String literals
• Enumeration constants
ANSWER
QUESTION 6
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What are the different types of c instructions?
8
QUESTION
• There are basically three types of instructions in C are :
• Type Declaration Instruction
• Arithmetic Instruction
• Control Instruction
ANSWER
QUESTION 7
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Why C is called a middle level language?
9
QUESTION
C combines the features of both Assembly Level Languages (Low Level Languages) and Higher Level Languages.
For this reason, C is referred to as a Middle Level Language. The feature of ALLs is that of enabling us to develop
system level programs and the features of HLLs are those of higher degree of readability and machine
independence.
ANSWER
QUESTION 8
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What is the purpose of main() function?
10
QUESTION
• The function main() invokes other functions within it. It is the first function to be called when the program starts
execution.
• It is the starting function.
• It returns an int value to the environment that called the program.
• Recursive call is allowed for main( ) also.
• It is a user-defined function.
ANSWER
QUESTION 9
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What is meant by type specifiers?
11
QUESTION
Type specifiers decide the amount of memory space occupied by a variable. In the ease of integral types; it also
explicitly states the range of values that the object can hold.
ANSWER
QUESTION 10
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What is the difference between single charater constant and string constant?
12
QUESTION
• A single character constant consists of only one character and it is enclosed within a pair of single quotes.
• A string constant consists of one or more characters and it is enclosed within a pair of double quotes.
ANSWER
QUESTION 11
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What is a loop?
13
QUESTION
A loop is a process to do a job repeatedly with possibly different data each time. The statements executed each time
constitute the loop body, and each pass is called iteration. A condition must be present to terminate the loop.
ANSWER
QUESTION 12
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What are the types of data types and explain?
14
QUESTION
There are five basic Data types in C. These are :
• void: means nothing i.e. no data involvement in an action
• char: to work with all types of characters used in computer operations
• int: to work with an integer type of data in any computational work
• float: to work with the real type of data or scientific numbers in the exponential form
• double: to work with double precision of numbers when the approximation is very crucial.
ANSWER
QUESTION 13
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What is the general form of a C program?
15
QUESTION
A C program begins with the preprocessor directives, in which the programmer would specify which header file and
what constants (if any) to be used. This is followed by the main function heading. Within the main function lies the
variable declaration and program statement.
ANSWER
QUESTION 14
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What is the difference between Call by Value and Call by Reference?
16
QUESTION
When using Call by Value, you are sending the value of a variable as parameter to a function, whereas Call by
Reference sends the address of the variable. Also, under Call by Value, the value in the parameter is not affected
by whatever operation that takes place, while in the case of Call by Reference, values can be affected by the
process within the function.
ANSWER
QUESTION 15
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What is a stack?
17
QUESTION
A stack is one form of a data structure. Data is stored in stacks using the FILO (First In Last Out) approach. At any
particular instance, only the top of the stack is accessible, which means that in order to retrieve data that is stored
inside the stack, those on the upper part should be extracted first. Storing data in a stack is also referred to as a
PUSH, while data retrieval is referred to as a POP.
ANSWER
QUESTION 16
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What is the use of a „\0′ character?
18
QUESTION
It is referred to as a terminating null character, and is used primarily to show the end of a string value.
ANSWER
QUESTION 17
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What is the difference between the = symbol and == symbol?
19
QUESTION
The = symbol is often used in mathematical operations. It is used to assign a value to a given variable. On the other
hand, the = = symbol, also known as “equal to” or “equivalent to”, is a relational operator that is used to compare
two values
ANSWER
QUESTION 18
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What is the modulus operator?
20
QUESTION
The modulus operator outputs the remainder of a division. It makes use of the percentage (%) symbol. For example:
10 % 3 = 1, meaning when you divide 10 by 3, the remainder is 1.
ANSWER
QUESTION 19
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Which of the following operators is incorrect and why? ( >=, <=, <>, ==)
21
QUESTION
<> is incorrect. While this operator is correctly interpreted as “not equal to” in writing conditional statements, it is not
the proper operator to be used in C programming. Instead, the operator != must be used to indicate “not equal
to” condition.
ANSWER
QUESTION 20
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What is syntax error?
22
QUESTION
Syntax errors are associated with mistakes in the use of a programming language. It maybe a command that was
misspelled or a command that must was entered in lowercase mode but was instead entered with an upper case
character. A misplaced symbol, or lack of symbol, somewhere within a line of code can also lead to syntax error.
ANSWER
QUESTION 21
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Can I use “int” data type to store the value 32768? Why?
23
QUESTION
No. “int” data type is capable of storing values from -32768 to 32767. To store 32768, you can use “long int” instead.
You can also use “unsigned int”, assuming you don‟t intend to store negative values.
ANSWER
QUESTION 22
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When is the “void” keyword used in a function?
24
QUESTION
When declaring functions, you will decide whether that function would be returning a value or not. If that function will
not return a value, such as when the purpose of a function is to display some outputs on the screen, then “void” is
to be placed at the leftmost part of the function header. When a return value is expected after the function
execution, the data type of the return value is placed instead of “void”.
ANSWER
QUESTION 23
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What is the significance of an algorithm to C programming?
25
QUESTION
Before a program can be written, an algorithm has to be created first. An algorithm provides a step by step
procedure on how a solution can be derived. It also acts as a blueprint on how a program will start and end,
including what process and computations are involved.
ANSWER
QUESTION 24
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How do you generate random numbers in C?
26
QUESTION
Random numbers are generated in C using the rand() command. For example: anyNum = rand() will generate any
integer number beginning from 0, assuming that anyNum is a variable of type integer.
ANSWER
QUESTION 25
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What is debugging?
27
QUESTION
Debugging is the process of identifying errors within a program. During program compilation, errors that are found
will stop the program from executing completely. At this state, the programmer would look into the possible
portions where the error occurred. Debugging ensures the removal of errors, and plays an important role in
ensuring that the expected program output is met.
ANSWER
QUESTION 26
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What does the && operator do in a program code?
28
QUESTION
The && is also referred to as AND operator. When using this operator, all conditions specified must be TRUE before
the next action can be performed. If you have 10 conditions and all but 1 fails to evaluate as TRUE, the entire
condition statement is already evaluated as FALSE.
ANSWER
QUESTION 27
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What is || operator and how does it function in a program?
29
QUESTION
The || is also known as the OR operator in C programming. When using || to evaluate logical conditions, any
condition that evaluates to TRUE will render the entire condition statement as TRUE.
ANSWER
QUESTION 28
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What will be the outcome of the following conditional statement if the value of
variable s is 10? s >=10 && s < 25 && s!=12
30
QUESTION
The outcome will be TRUE. Since the value of s is 10, s >= 10 evaluates to TRUE because s is not greater than 10
but is still equal to 10. s< 25 is also TRUE since 10 is less then 25. Just the same, s!=12, which means s is not
equal to 12, evaluates to TRUE. The && is the AND operator, and follows the rule that if all individual conditions
are TRUE, the entire statement is TRUE.
ANSWER
QUESTION 29
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What is FIFO?
31
QUESTION
In C programming, there is a data structure known as queue. In this structure, data is stored and accessed using
FIFO format, or First-In-First-Out. A queue represents a line wherein the first data that was stored will be the first
one that is accessible as well.
ANSWER
QUESTION 30
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In C language, the variables NAME, name, and Name are all the same. TRUE or
FALSE?
32
QUESTION
FALSE. C language is a case sensitive language. Therefore, NAME, name and Name are three uniquely different
variables.
ANSWER
QUESTION 31
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When is a “switch” statement preferable over an “if” statement?
33
QUESTION
The switch statement is best used when dealing with selections based on a single variable or expression. However,
switch statements can only evaluate integer and character data types.
ANSWER
QUESTION 32
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What is gets() function?
34
QUESTION
The gets() function allows a full line data entry from the user. When the user presses the enter key to end the input,
the entire line of characters is stored to a string variable. Note that the enter key is not included in the variable, but
instead a null terminator \0 is placed after the last character.
ANSWER
QUESTION 33
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Difference between Syntax and logical error?
35
QUESTION
Syntax error:
These involves validation of syntax of language
Compiler prints diagnostic message.
Logical error:
Logical error are caused by an incorrect algorithm or by a statement mistyped in such a way that it doesn‟t violet
syntax of language.
It is difficult to find.
ANSWER
QUESTION 34
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What is static memory allocation?
36
QUESTION
Compiler allocates memory space for a declared variable. By using the address of operator, the reserved address is
obtained and this address is assigned to a pointer variable. This way of assigning pointer value to a pointer
variable at compilation time is known as static memory allocation.
ANSWER
QUESTION 35
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What is dynamic memory allocation?
37
QUESTION
A dynamic memory allocation uses functions such as malloc() or calloc() to get memory dynamically. If these
functions are used to get memory dynamically and the values returned by these function are assigned to pointer
variables, such a way of allocating memory at run time is known as dynamic memory allocation.
ANSWER
QUESTION 36
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Are Pointers Integer?
38
QUESTION
No, Pointers are not integers. A pointer is an address. It is a positive number.
ANSWER
QUESTION 37
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In header files whether functions are declared or defined?
39
QUESTION
Functions are declared within header file. That is function prototypes exist in a header file, not function bodies. They
are defined in library (lib).
ANSWER
QUESTION 38
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Difference between strdup and strcpy?
40
QUESTION
Both copy a string. Strcpy wants a buffer to copy into. Strdup allocates a buffer using malloc(). Unlike strcpy(),
strdup() is not specified by ANSI.
ANSWER
QUESTION 39
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What is spaghetti programming?
41
QUESTION
Spaghetti programming refers to codes that tend to get tangled and overlapped throughout the program. This
unstructured approach to coding is usually attributed to lack of experience on the part of the programmer.
Spaghetti programing makes a program complex and analyzing the codes difficult, and so must be avoided as
much as possible.
ANSWER
QUESTION 40
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In C programming, how do you insert quote characters („ and “) into the output
screen?
42
QUESTION
This is a common problem for beginners because quotes are normally part of a printf statement. To insert the quote
character as part of the output, use the format specifiers‟ (for single quote), and ” (for double quote).
ANSWER
QUESTION 41
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What is a nested loop?
43
QUESTION
A nested loop is a loop that runs within another loop. Put it in another sense, you have an inner loop that is inside an
outer loop. In this scenario, the inner loop is performed a number of times as specified by the outer loop. For each
turn on the outer loop, the inner loop is first performed.
ANSWER
QUESTION 42
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Can the curly brackets { } be used to enclose a single line of code?
44
QUESTION
While curly brackets are mainly used to group several lines of codes, it will still work without error if you used it for a
single line. Some programmers prefer this method as a way of organizing codes to make it look clearer, especially
in conditional statements.
ANSWER
QUESTION 43
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What are compound statements?
45
QUESTION
Compound statements are made up of two or more program statements that are executed together. This usually
occurs while handling conditions wherein a series of statements are executed when a TRUE or FALSE is
evaluated. Compound statements can also be executed within a loop. Curly brackets { } are placed before and
after compound statements.
ANSWER
QUESTION 44
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What is a register variable?
46
QUESTION
Register variables are stored in the CPU registers. Its default value is a garbage value. Scope of a register variable
is local to the block in which it is defined. Lifetime is till control remains within the block in which the register
variable is defined. Variable stored in a CPU register can always be accessed faster than the one that is stored in
memory. Therefore, if a variable is used at many places in a program, it is better to declare its storage class as
register
Example: register int x=5;
Variables for loop counters can be declared as register. Note that register keyword may be ignored by some
compilers.
ANSWER
QUESTION 45
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What is size of void pointer?
47
QUESTION
Size of any type of pointer in c is independent of data type which is pointer is pointing i.e. size of all type of pointer
(near) in c is two byte either it is char pointer, double pointer, function pointer or null pointer. Void pointer is not
exception of this rule and size of void pointer is also two byte.
ANSWER
QUESTION 46
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What are printf and scanf, call by reference or call by value?
48
QUESTION
Printf : Call by value
Scanf : Call by reference
ANSWER
QUESTION 47
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What is a const pointer?
49
QUESTION
a const pointer means the pointer which represents the address of one value. so if you declare a pointer inside the
function, it doesn't have scope outside the function. if it is also available to the outside function whenever we
declare a pointer as const.
ANSWER
QUESTION 48
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Why does n++ execute much faster than n+1?
50
QUESTION
n++ takes more than one instruction, ++n is faster. n++ has to store n, increment the variable and return n, while
++n increment n and return without storing the previous value of n.
ANSWER
QUESTION 49
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What is modular Programming?
51
QUESTION
If a program is large, it is subdivided into a number of smaller programs that are called modules or subprograms. If a
complex problem is solved using more modules, this approach is known as modular programming.
ANSWER
QUESTION 51
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Why doesn't C support function overloading?
52
QUESTION
Overloading is polymorphism which is one of the characteristics of Object oriented programming. C is not and object
oriented language like C++ or Java. Therefore, no overloading, inheritance, etc.
ANSWER
QUESTION 51
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What is an incomplete type?
53
QUESTION
Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location
or it points to some location whose value is not available for modification.
ANSWER
QUESTION 52
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Explain the Difference between C and C++?
54
QUESTION
C is the predecessor of C++. C++ is an Object Oriented, non-procedural language, unlike C, which is a procedural
language. C++ treats all data and functional handling in terms of Objects and their relationships.
ANSWER
QUESTION 53
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What is Nesting in C?
55
QUESTION
Including one constructed inside another, is nesting. Nesting can be a structure inside another structure, an if-else
statement within another, multiple while loops, one inside the other. Continuing our earlier example, if you have a
collection of bikes, instead of grouping them separately, you can nest them within a main structure, which you can
name “Collection of Bikes”.
ANSWER
QUESTION 54
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How is calloc () different from malloc ()?
56
QUESTION
The main difference between the two is that calloc (), when it is used to assign a block of memory, the allocated
contents are initialized to 0. Malloc (), on the other hand, does not initialise the memory block it assigns. The
memory just has random values left over from previous usage.
ANSWER
QUESTION 55
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What are Destructors in C Language?
57
QUESTION
Classifying a destructor you can call it a class object and it is called a destructor once it goes out of scope or gets
deleted overtly. The job of a destructor is to put an end to objects being produced by a constructor. Just like the
constructor you can consider destructor a functional member and it is specifically known by a class name.
ANSWER
QUESTION 56
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What are the uses of a pointer?
58
QUESTION
Pointer is used in the following cases
i) It is used to access array elements
ii) It is used for dynamic memory allocation.
iii) It is used in Call by reference
iv) It is used in data structures like trees, graph, linked list etc.
ANSWER
QUESTION 57
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What is a union?
59
QUESTION
Union is a collection of heterogeneous data type but it uses efficient memory utilization technique by allocating
enough memory to hold the largest member. Here a single area of memory contains values of different types at
different time. A union can never be initialized.
ANSWER
QUESTION 58
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What are macros? What are its advantages and disadvantages?
60
QUESTION
Macros are abbreviations for lengthy and frequently used statements. When a macro is called the entire code is
substituted by a single line though the macro definition is of several lines.
The advantage of macro is that it reduces the time taken for control transfer as in case of function.
The disadvantage of it is here the entire code is substituted so the program becomes lengthy if a macro is called
several times.
ANSWER
QUESTION 59
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What are enumerations?
61
QUESTION
They are a list of named integer-valued constants. Example:enum color { black , orange=4, yellow, green, blue,
violet }; This declaration defines the symbols “black”, “orange”, “yellow”, etc. to have the values “1,” “4,” “5,” … etc.
The difference between an enumeration and a macro is that the enum actually declares a type, and therefore can
be type checked.
ANSWER
QUESTION 60
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What is the use of typedef?
62
QUESTION
The typedef help in easier modification when the programs are ported to another machine. A descriptive new name
given to the existing data type may be easier to understand the code.
ANSWER
QUESTION 61
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What is the difference between Strings and Arrays?
63
QUESTION
String is a sequence of characters ending with NULL .it can be treated as a one dimensional array of characters
terminated by a NULL character.
ANSWER
QUESTION 62
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What is a normalized pointer, how do we normalize a pointer?
64
QUESTION
It is a 32bit pointer, which has as much of its value in the segment registered as possible. Since a segment can start
every 16bytes so the offset will have a value from 0 to F. for normalization convert the address into 20bit address
then use the 16bit for segment address and 4bit for the offset address. Given a pointer 500D: 9407, we convert it
to a 20bitabsolute address 549D7,Which then normalized to 549D:0007.
ANSWER
QUESTION 63
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What is generic pointer in C?
65
QUESTION
In C void* acts as a generic pointer. When other pointer types are assigned to generic pointer, conversions are
applied automatically (implicit conversion).
ANSWER
QUESTION 64
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Difference between linker and linkage?
66
QUESTION
Linker converts an object code into an executable code by linking together the necessary built in functions. The form
and place of declaration where the variable is declared in a program determine the linkage of variable.
ANSWER
QUESTION 65
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What is a function?
67
QUESTION
A large program is subdivided into a number of smaller programs or subprograms. Each subprogram specifies one
or more actions to be performed for the larger program. Such sub programs are called functions.
ANSWER
QUESTION 66
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What is an argument?
68
QUESTION
An argument is an entity used to pass data from the calling to a called function.
ANSWER
QUESTION 67
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Write a program which employs Recursion?
69
QUESTION
int fact(int n) { return n > 1 ? n * fact(n – 1) : 1; }
ANSWER
QUESTION 68
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What do the „c‟ and „v‟ in argc and argv stand for?
70
QUESTION
The c in argc(argument count) stands for the number of command line argument the program is invoked with and v
in argv(argument vector) is a pointer to an array of character string that contain the arguments.
ANSWER
QUESTION 69
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What are C identifiers?
71
QUESTION
These are names given to various programming element such as variables, function, arrays.It is a combination of
letter, digit and underscore.It should begin with letter. Backspace is not allowed.
ANSWER
QUESTION 70
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What do the functions atoi(), itoa() and gcvt() do?
72
QUESTION
atoi() is a macro that converts integer to character.
itoa() It converts an integer to string
gcvt() It converts a floating point number to string
ANSWER
QUESTION 71
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How is fopen() used ?
73
QUESTION
The function fopen() returns a file pointer. Hence a file pointer is declared and it is assigned as
FILE *fp;
fp= fopen(filename,mode);
filename is a string representing the name of the file and the mode represents:
“r” for read operation
“w” for write operation
“a” for append operation
“r+”,”w+”,”a+” for update operation
ANSWER
QUESTION 72
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What is the purpose of ftell ?
74
QUESTION
The function ftell() is used to get the current file represented by the file pointer.
ftell(fp);
returns a long integer value representing the current file position of the file pointed by the
file pointer fp.If an error occurs ,-1 is returned.
ANSWER
QUESTION 73
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Discuss on pointer arithmetic?
75
QUESTION
1. Assignment of pointers to the same type of pointers.
2. Adding or subtracting a pointer and an integer.
3. Subtracting or comparing two pointer.
4. Incrementing or decrementing the pointers pointing to the elements of an array. When a pointer to an integer is
incremented by one , the address is incremented by two. It is done automatically by the compiler.
5. Assigning the value 0 to the pointer variable and comparing 0 with the pointer. The pointer having address 0
points to nowhere at all.
ANSWER
QUESTION 74
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What is the invalid pointer arithmetic?
76
QUESTION
i) adding ,multiplying and dividing two pointers.
ii) Shifting or masking pointer.
iii) Addition of float or double to pointer.
iv) Assignment of a pointer of one type to a pointer of another type ?
ANSWER
QUESTION 75
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Can we initialize unions?
77
QUESTION
ANSI Standard C allows an initializer for the first member of a union. There is no standard way of initializing any
other member (nor, under a pre-ANSI compiler, is there generally any way of initializing a union at all).
ANSWER
QUESTION 76
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What is Output of following c snippet?
int main(){
char *s="Abhas";
printf("%s",s+ 2);
getch();
}
78
QUESTION
Has. Explanation: In the above program role of %s is to display the string whose address is passed as an
argument. This is how a standard printf statement works in c language. Now since we have passed s + 2 as an
argument therefore first value of this expression is evaluated. Here „s‟ would refer to address of first character in
string „s‟. Now printf would get address of third character (address of first character + 2) as argument so it will
display the string starting from third position. Hence output would be „has‟.
ANSWER
QUESTION 77
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What is difference between .com program and .exe program?
79
QUESTION
Both .com and .exe program are executable program but .com program executes faster than .exe program. All
drivers are .com program. .com file has higher preference than .exe.
ANSWER
QUESTION 78
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Describe turbo c Compiler?
80
QUESTION
Turbo c is an IDE programming language created by Borland. Turbo C 3.0 is based on MS DOS operation system. It
is one of the most popular c compilers. It uses 8086 microprocessor which is 16 bit microprocessor. It has 20
address buses and 16 data bus. Its word length is two byte.
ANSWER
QUESTION 79
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Out of fgets() and gets() which function is safe to use and why?
81
QUESTION
Fgets() is safer than gets(), because we can specify a maximum input length. Neither one is completely safe,
because the compiler can‟t prove that programmer won‟t overflow the buffer he pass to fgets ().
ANSWER
QUESTION 80
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Differentiate between a “for loop” and a “while loop”?
82
QUESTION
For executing a set of statements fixed number of times we use “for loop” while when the number of iterations to be
performed is not known in advance we use “while loop”.
ANSWER
QUESTION 81
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Is there a built-in function in C that can be used for sorting data?
83
QUESTION
Yes, use the qsort() function. It is also possible to create user defined functions for sorting, such as those based on
the balloon sort and bubble sort algorithm.
ANSWER
QUESTION 82
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What are the advantages and disadvantages of a heap?
84
QUESTION
Storing data on the heap is slower than it would take when using the stack. However, the main advantage of using
the heap is its flexibility. That‟s because memory in this structure can be allocated and remove in any particular
order. Slowness in the heap can be compensated if an algorithm was well designed and implemented.
ANSWER
QUESTION 83
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How do you convert strings to numbers in C?
85
QUESTION
You can write you own functions to do string to number conversions, or instead use C‟s built in functions. You can
use atof to convert to a floating point value, atoi to convert to an integer value, and atol to convert to a long integer
value.
ANSWER
QUESTION 84
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Create a simple code fragment that will swap the values of two variables num1 and
num2.
86
QUESTION
int temp;
temp = num1;
num1 = num2;
num2 = temp;
ANSWER
QUESTION 85
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What is the use of a semicolon (;) at the end of every program statement?
87
QUESTION
It has to do with the parsing process and compilation of the code. A semicolon acts as a delimiter, so that the
compiler knows where each statement ends, and can proceed to divide the statement into smaller elements for
syntax checking.
ANSWER
QUESTION 86
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What does the characters “r” and “w” mean when writing programs that will make
use of files?
88
QUESTION
“r” means “read” and will open a file as input wherein data is to be retrieved. “w” means “write”, and will open a file
for output. Previous data that was stored on that file will be erased.
ANSWER
QUESTION 87
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Which function in C can be used to append a string to another string?
89
QUESTION
The strcat function. It takes two parameters, the source string and the string value to be appended to the source
string.
ANSWER
QUESTION 88
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What is the difference between functions getch() and getche()?
90
QUESTION
Both functions will accept a character input value from the user. When using getch(), the key that was pressed will
not appear on the screen, and is automatically captured and assigned to a variable. When using getche(), the key
that was pressed by the user will appear on the screen, while at the same time being assigned to a variable.
ANSWER
QUESTION 89
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What does the function toupper() do?
91
QUESTION
It is used to convert any letter to its upper case mode. Toupper() function prototype is declared in <ctype.h>. Note
that this function will only convert a single character, and not an entire string.
ANSWER
QUESTION 90
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What are run-time errors?
92
QUESTION
These are errors that occur while the program is being executed. One common instance wherein run-time errors can
happen is when you are trying to divide a number by zero. When run-time errors occur, program execution will
pause, showing which program line caused the error.
ANSWER
QUESTION 91
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Is this program statement valid? INT = 10.50;
93
QUESTION
Assuming that INT is a variable of type float, this statement is valid. One may think that INT is a reserved word and
must not be used for other purposes. However, recall that reserved words are express in lowercase, so the C
compiler will not interpret this as a reserved word.
ANSWER
QUESTION 92
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What is wrong with this program statement? void = 10;
94
QUESTION
The word void is a reserved word in C language. You cannot use reserved words as a user-defined variable.
ANSWER
QUESTION 93
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What would happen to X in this expression: X += 15; (assuming the value of X is 5)
95
QUESTION
X +=15 is a short method of writing X = X + 15, so if the initial value of X is 5, then 5 + 15 = 20.
ANSWER
QUESTION 94
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Not all reserved words are written in lowercase. TRUE or FALSE?
96
QUESTION
FALSE. All reserved words must be written in lowercase; otherwise the C compiler would interpret this as
unidentified and invalid.
ANSWER
QUESTION 95
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What is floating point constants?
97
QUESTION
Floating-point constants are numbers with decimal parts. A floating-point constants consists of :
An integral part
A decimal point
A fractional part
An exponent part
An optional suffix
ANSWER
QUESTION 96
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What is the difference between fread and fwrite function?
98
QUESTION
The fread() function returns the number of items read. This value may be less than count if the end of the file is
reached or an error occurs. The fwrite() function returns the number of items written. This value will equal count
unless an error occurs.
ANSWER
QUESTION 97
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What is meant by inheritance?
99
QUESTION
Inheritance is the process by which objects of one class acquire properties of objects of another class.
ANSWER
QUESTION 98
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What is a ternary operator in C?
100
QUESTION
Perhaps the most unusual operator in C language is one called the conditional expression operator. Unlike all other
operators in C which are either unary or binary operators the conditional expression operator is a ternary operator;
that is, it takes three operands. The two symbols that are used to denote this operator are the question mark (?)
and the colon (:). The first operand is placed before the ?, the second between the ? and the and the third after
the:.
ANSWER
QUESTION 99
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What is unary operator?
101
QUESTION
The operators that act upon a single operand to produce a new value are known as unary operators.
ANSWER
QUESTION 100
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Resources
102
http://www.fresherventure.net/frequently-asked-c-language-interview-questions-and-answers/http://www.itechaleart.com/2014/06/top-100-c-interview-qa.htmlhttp://placement.freshersworld.com/power-preparation/technical-interview-questions/C-programming-answers-21419http://career.guru99.com/top-100-c-interview-questions-answers/http://www.slideshare.net/vineetkumarsaini/top-c-language-interview-questions-and-answerhttp://www.cquestions.com/2010/10/c-interview-questions-and-answers.htmlhttp://placementsindia.blogspot.com/2007/10/basic-c-interview-questions.htmlhttps://www.udemy.com/blog/c-programming-questions/http://crackaninterview.com/c-language-interview-questions/http://www.cwithabhas.com/2013/09/simple-c-interview-questions-for-mass.htmlhttp://www.freejobalert.com/c-interview-questions/2891/
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