Top 100 C Questions Asked in Actual Interviews

Difference between arrays and pointers?
http://www.coolinte rview.com/ interview/ 960

What is the purpose of realloc( )?
http://www.coolinte rview.com/ interview/ 961

What is static memory allocation and dynamic memory allocation?
http://www.coolinte rview.com/ interview/ 962

How are pointer variables initialized?
http://www.coolinte rview.com/ interview/ 963

Are pointers integers?
http://www.coolinte rview.com/ interview/ 964

What is a pointer variable?
http://www.coolinte rview.com/ interview/ 965

What is a pointer value and address?
http://www.coolinte rview.com/ interview/ 966

What is a method?
http://www.coolinte rview.com/ interview/ 967

What are the advantages of the functions?
http://www.coolinte rview.com/ interview/ 968

What is the purpose of main( ) function?
http://www.coolinte rview.com/ interview/ 969

What is an argument ? differentiate between formal arguments and actual arguments?
http://www.coolinte rview.com/ interview/ 970

What is a function and built-in function?
http://www.coolinte rview.com/ interview/ 971

What is modular programming?
http://www.coolinte rview.com/ interview/ 972

When does the compiler not implicitly generate the address of the first element of an array?
http://www.coolinte rview.com/ interview/ 973

What are the characteristics of arrays in C?
http://www.coolinte rview.com/ interview/ 974

Differentiate between a linker and linkage?
http://www.coolinte rview.com/ interview/ 975

What are advantages and disadvantages of external storage class?
http://www.coolinte rview.com/ interview/ 976

Diffenentiate between an internal static and external static variable?
http://www.coolinte rview.com/ interview/ 977

What are the advantages of auto variables?
http://www.coolinte rview.com/ interview/ 978

What is storage class and what are storage variable ?
http://www.coolinte rview.com/ interview/ 979

Which expression always return true? Which always return false?
http://www.coolinte rview.com/ interview/ 980

Write the equivalent expression for x%8?
http://www.coolinte rview.com/ interview/ 981

why n++ executes faster than n+1?
http://www.coolinte rview.com/ interview/ 982

what is a modulus operator? What are the restrictions of a modulus operator?
http://www.coolinte rview.com/ interview/ 983

What is the difference between a string and an array?
http://www.coolinte rview.com/ interview/ 984

Is it better to use a pointer to navigate an array of values,or is it better to use a subscripted array name?
http://www.coolinte rview.com/ interview/ 985

Can the sizeof operator be used to tell the size of an array passed to a function?
http://www.coolinte rview.com/ interview/ 986

Is using exit() the same as using return?
http://www.coolinte rview.com/ interview/ 987

Is it possible to execute code even after the program exits the main() function?
http://www.coolinte rview.com/ interview/ 988

What is a static function?
http://www.coolinte rview.com/ interview/ 989

Why should I prototype a function?
http://www.coolinte rview.com/ interview/ 990

How do you print an address?
http://www.coolinte rview.com/ interview/ 991

Can math operations be performed on a void pointer?
http://www.coolinte rview.com/ interview/ 992

How can you determine the size of an allocated portion of memory?
http://www.coolinte rview.com/ interview/ 993

What is a �null pointer assignment� error? What are bus errors, memory faults, and core dumps?
http://www.coolinte rview.com/ interview/ 994

What is the difference between NULL and NUL?
http://www.coolinte rview.com/ interview/ 995

What is the heap?
http://www.coolinte rview.com/ interview/ 996

Can the size of an array be declared at runtime?
http://www.coolinte rview.com/ interview/ 997

What is the stack?
http://www.coolinte rview.com/ interview/ 998

When should a far pointer be used?
http://www.coolinte rview.com/ interview/ 999

What is the difference between far and near?
http://www.coolinte rview.com/ interview/ 1000

Is it better to use malloc() or calloc()?
http://www.coolinte rview.com/ interview/ 1001

Why should we assign NULL to the elements (pointer) after freeing them?
http://www.coolinte rview.com/ interview/ 1002

When would you use a pointer to a function?
http://www.coolinte rview.com/ interview/ 1003

How do you use a pointer to a function?
http://www.coolinte rview.com/ interview/ 1004

Can you add pointers together? Why would you?
http://www.coolinte rview.com/ interview/ 1005

What does it mean when a pointer is used in an if statement?
http://www.coolinte rview.com/ interview/ 1006

Is NULL always defined as 0?
http://www.coolinte rview.com/ interview/ 1007

What is a void pointer?
http://www.coolinte rview.com/ interview/ 1008

What is a null pointer?
http://www.coolinte rview.com/ interview/ 1009

How many levels of pointers can you have?
http://www.coolinte rview.com/ interview/ 1010

What is indirection?
http://www.coolinte rview.com/ interview/ 1011

How do you print only part of a string?
http://www.coolinte rview.com/ interview/ 1012

How can I convert a string to a number?
http://www.coolinte rview.com/ interview/ 1013

How can I convert a number to a string?
http://www.coolinte rview.com/ interview/ 1014

What is the difference between a string copy (strcpy) and a memory copy (memcpy)? When should each be used?
http://www.coolinte rview.com/ interview/ 1015

How can you check to see whether a symbol is defined?
http://www.coolinte rview.com/ interview/ 1016

How do you override a defined macro?
http://www.coolinte rview.com/ interview/ 1017

What is #line used for?
http://www.coolinte rview.com/ interview/ 1018

What is a pragma?
http://www.coolinte rview.com/ interview/ 1019

What are the standard predefined macros?
http://www.coolinte rview.com/ interview/ 1020

How can type-insensitive macros be created?
http://www.coolinte rview.com/ interview/ 1021

How many levels deep can include files be nested?
http://www.coolinte rview.com/ interview/ 1022

Can include files be nested?
http://www.coolinte rview.com/ interview/ 1023

Can you define which header file to include at compile time?
http://www.coolinte rview.com/ interview/ 1024

What is the difference between #include and #include �file�?
http://www.coolinte rview.com/ interview/ 1025

Is it better to use a macro or a function?
http://www.coolinte rview.com/ interview/ 1026

How are portions of a program disabled in demo versions?
http://www.coolinte rview.com/ interview/ 1027

What is the benefit of using an enum rather than a #define constant?
http://www.coolinte rview.com/ interview/ 1028

What is the benefit of using #define to declare a constant?
http://www.coolinte rview.com/ interview/ 1029

Can a file other than a .h file be included with #include?
http://www.coolinte rview.com/ interview/ 1030

How can you avoid including a header more than once?
http://www.coolinte rview.com/ interview/ 1031

What will the preprocessor do for a program?
http://www.coolinte rview.com/ interview/ 1032

What is a macro, and how do you use it?
http://www.coolinte rview.com/ interview/ 1033

What is Preprocessor?
http://www.coolinte rview.com/ interview/ 1034

How can I make sure that my program is the only one accessing a file?
http://www.coolinte rview.com/ interview/ 1035

How can I open a file so that other programs can update it at the same time?
http://www.coolinte rview.com/ interview/ 1036

How do you determine whether to use a stream function or a low-level function?
http://www.coolinte rview.com/ interview/ 1037

What is the difference between text and binary modes?
http://www.coolinte rview.com/ interview/ 1038

How can you restore a redirected standard stream?
http://www.coolinte rview.com/ interview/ 1039

How do you redirect a standard stream?
http://www.coolinte rview.com/ interview/ 1040

How can I search for data in a linked list?
http://www.coolinte rview.com/ interview/ 1041

How can I sort a linked list?
http://www.coolinte rview.com/ interview/ 1042

What is hashing?
http://www.coolinte rview.com/ interview/ 1043

What is the quickest searching method to use?
http://www.coolinte rview.com/ interview/ 1044

What is the easiest searching method to use?
http://www.coolinte rview.com/ interview/ 1045

How can I sort things that are too large to bring into memory?
http://www.coolinte rview.com/ interview/ 1046

What is the quickest sorting method to use?
http://www.coolinte rview.com/ interview/ 1047

What is the easiest sorting method to use?
http://www.coolinte rview.com/ interview/ 1048

What is the benefit of using const for declaring constants?
http://www.coolinte rview.com/ interview/ 1049

Can static variables be declared in a header file?
http://www.coolinte rview.com/ interview/ 1050

What is the difference between declaring a variable and defining a variable?
http://www.coolinte rview.com/ interview/ 1051

Is it acceptable to declare/define a variable in a C header?
http://www.coolinte rview.com/ interview/ 1052

When should a type cast not be used?
http://www.coolinte rview.com/ interview/ 1053

When should a type cast be used?
http://www.coolinte rview.com/ interview/ 1054

How can you determine the maximum value that a numeric variable can hold?
http://www.coolinte rview.com/ interview/ 1055

How reliable are floating-point comparisons?
http://www.coolinte rview.com/ interview/ 1056

Can a variable be both const and volatile?
http://www.coolinte rview.com/ interview/ 1057

when should the volatile modifier be used?
http://www.coolinte rview.com/ interview/ 1058

When should the register modifier be used? Does it really help? http://www.coolinte rview.com/ interview/ 1059