Techincal Interview Questions - C Launguage

General Technical C Questions :

· What does static variable mean?
· What is a pointer?
· What is a structure?
· What are the differences between structures and arrays?
· In header files whether functions are declared or defined?
· What are the differences between malloc() and calloc()?
· What are macros? what are its advantages and disadvantages?
· Difference between pass by reference and pass by value?
· What is static identifier?
· Where are the auto variables stored?
· Where does global, static, local, register variables, free memory and C Program instructions get stored?
· Difference between arrays and linked list?
· What are enumerations?
· Describe about storage allocation and scope of global, extern, static, local and register variables?
· What are register variables? What are the advantage of using register variables?
· What is the use of typedef?
· Can we specify variable field width in a scanf() format string? If possible how?
· Out of fgets() and gets() which function is safe to use and why?
· Difference between strdup and strcpy?
· What is recursion?
· Differentiate between a for loop and a while loop? What are it uses?
· What are the different storage classes in C?
· Write down the equivalent pointer expression for referring the same element a[j][k][l]?
[*]· What is difference between Structure and Unions?
[*]· What the advantages of using Unions?
[*]· What are the advantages of using pointers in a program?
[*]· What is the difference between Strings and Arrays?
[*]· In a header file whether functions are declared or defined?
[*]· What is a far pointer? where we use it?
[*]· How will you declare an array of three function pointers where each function receives two ints and returns a float?
[*]· what is a NULL Pointer? Whether it is same as an uninitialized pointer?
[*]· What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?
[*]· What does the error 'Null Pointer Assignment' mean and what causes this error?
[*]· What is near, far and huge pointers? How many bytes are occupied by them?
[*]· How would you obtain segment and offset addresses from a far address of a memory location?
[*]· Are the expressions arr and &arr same for an array of integers?
[*]· Does mentioning the array name gives the base address in all the contexts?
[*]· Explain one method to process an entire string as one unit?
[*]· What is the similarity between a Structure, Union and enumeration?
[*]· Can a Structure contain a Pointer to itself?
[*]· How can we check whether the contents of two structure variables are same or not?
[*]· How are Structure passing and returning implemented by the complier?
[*]· How can we read/write Structures from/to data files?
[*]· What is the difference between an enumeration and a set of pre-processor # defines?
[*]· what do the 'c' and 'v' in argc and argv stand for?
[*]· Are the variables argc and argv are local to main?
[*]· What is the maximum combined length of command line arguments including the space between adjacent arguments?
[*]· If we want that any wildcard characters in the command line arguments should be appropriately expanded, are we required to make any special provision? If yes, which?
[*]· Does there exist any way to make the command line arguments available to other functions without passing them as arguments to the function?
[*]· What are bit fields? What is the use of bit fields in a Structure declaration?
[*]· To which numbering system can the binary number 1101100100111100 be easily converted to?
[*]· Which bit wise operator is suitable for checking whether a particular bit is on or off?
[*]· Which bit wise operator is suitable for turning off a particular bit in a number?
[*]· Which bit wise operator is suitable for putting on a particular bit in a number?
[*]· Which bit wise operator is suitable for checking whether a particular bit is on or off?
[*]· which one is equivalent to multiplying by 2:Left shifting a number by 1 or Left shifting an unsigned int or char by 1?
[*]· Write a program to compare two strings without using the strcmp() function.
[*]· Write a program to concatenate two strings.
[*]· Write a program to interchange 2 variables without using the third one.
[*]· Write programs for String Reversal & Palindrome check
[*]· Write a program to find the Factorial of a number
[*]· Write a program to generate the Fibinocci Series
[*]· Write a program which employs Recursion
[*]· Write a program which uses Command Line Arguments
[*]· Write a program which uses functions like strcmp(), strcpy()? etc
[*]· What are the advantages of using typedef in a program?
[*]· How would you dynamically allocate a one-dimensional and two-dimensional array of integers?
[*]· How can you increase the size of a dynamically allocated array?
[*]· How can you increase the size of a statically allocated array?
[*]· When reallocating memory if any other pointers point into the same piece of memory do you have to readjust these other pointers or do they get readjusted automatically?
[*]· Which function should be used to free the memory allocated by calloc()?
[*]· How much maximum can you allocate in a single call to malloc()?
[*]· Can you dynamically allocate arrays in expanded memory?
[*]· What is object file? How can you access object file?
[*]· Which header file should you include if you are to develop a function which can accept variable number of arguments?
[*]· Can you write a function similar to printf()?
[*]· How can a called function determine the number of arguments that have been passed to it?
[*]· Can there be at least some solution to determine the number of arguments passed to a variable argument list function?
[*]· How do you declare the following : "An array of three pointers to chars", "An array of three char pointers" , "A pointer to array of three chars", "A pointer to function which receives an int pointer and returns a float pointer" , "A pointer to a function which receives nothing and returns nothing".
[*]· What do the functions atoi(), itoa() and gcvt() do?
[*]· Does there exist any other function which can be used to convert an integer or a float to a string?
[*]· How would you use qsort() function to sort an array of structures?
[*]· How would you use qsort() function to sort the name stored in an array of pointers to string?
[*]· How would you use bsearch() function to search a name stored in array of pointers to string?
[*]· How would you use the functions sin(), pow(), sqrt()?
[*]· How would you use the functions memcpy(), memset(), memmove()?
[*]· How would you use the functions fseek(), freed(), fwrite() and ftell()?
[*]· How would you obtain the current time and difference between two times?
[*]· How would you use the functions randomize() and random()?
[*]· How would you implement a substr() function that extracts a sub string from a given string?
[*]· What is the difference between the functions rand(), random(), srand() and randomize()?
[*]· What is the difference between the functions memmove() and memcpy()?
[*]· How do you print a string on the printer?
[*]· Can you use the function fprintf() to display the output on the screen?