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C Programming – Technical interview questions

What does the error ‘Null PointerAssignment’ mean and what causes this error?
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 ornot?
How are Structure passing and returning implemented by the compiler?
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 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 amemory 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?
What is the maximum combined length of command line arguments including thespace between adjacent arguments?
If we want that any wildcard characters in the command line arguments should beappropriately 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 otherfunctions 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 easilyconverted to?
Which bit wise operator is suitable for checking whether a particular bit is onor off?
Which bit wise operator is suitable for turning off a particular bit in anumber?
Which bit wise operator is suitable for putting on a particular bit in anumber?
Which bit wise operator is suitable for checking whether a particular bit is onor off?
which one is equivalent to multiplying by 2:Left shifting a number by 1 or Leftshifting 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.
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 Programinstructions get stored?
Difference between arrays and linked list?
What are enumerations?
Describe about storage allocation and scope of global, extern, static, localand register variables?
What are register variables? What are the advantage of using registervariables?
What is the use of typedef?
Can we specify variable field width in a scanf() format string? If possiblehow?
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 elementa[i][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 functionreceives 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 NULLMacro?
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 arrayof 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 ofmemory do you have to readjust these other pointers or do they get readjustedautomatically?
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 canaccept variable number of arguments?
Can you write a function similar to printf()?
How can a called function determine the number of arguments that have beenpassed to it?
Can there be at least some solution to determine the number of arguments passedto 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 ora 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 ofpointers to string?
How would you use bsearch() function to search a name stored in array ofpointers 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 agiven string?
What is the difference between the functions rand(), random(), srand() andrandomize()?
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?

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Aptitude Test Practice Questions - With Answers

Question 1. Which of the following is least like the others?
A.    cube
B.    sphere
C.    pyramid
D.    circle

D (because the circle is the only two-dimensional figure)

Question 2. Consider a language which uses the following set of characters:
Small set: { a b c }
Large set: { A B C }
Punctuation set: { x y }
This language must follow the following rules:
  1.    A punctuation character must end all series.
  2.    A series can have up to but no more than 4          characters,including punctuation characters.

Does the following series follow all the rules of the language defined above?
  A.    Yes
  B.    No

A (the series has only four characters and ends in a punctuation character)

Question 3. Consider the following flow chart for a customer:

The person in No.1 is:
    A.   Married, with children
    B.   Married, with at least one son
    C.   Unmarried, with at least one daughter
    D.   Unmarried, with at least one son
    E.   Unmarried, with no children