Frequently Asked Questions - Object oriented Concepts

• How do you write a program which produces its own source code as its output?



• How can I find the day of the week given the date?



• Why doesn't C have nested functions?



• What is the most efficient way to count the number of bits which are set in a value?



• How can I convert integers to binary or hexadecimal?



• How can I call a function, given its name as a string?



• How do I access command-line arguments?



• How can I return multiple values from a function?



• How can I invoke another program from within a C program?



• How can I access memory located at a certain address?



• How can I allocate arrays or structures bigger than 64K?



• How can I find out how much memory is available?



• How can I read a directory in a C program?



• How can I increase the allowable number of simultaneously open files?



• What's wrong with the call "fopen("c:\newdir\file.dat", "r")"?



• What is the output of printf("%d")



• What will happen if I say delete this



• Difference between "C structure" and "C++ structure".



• Diffrence between a "assignment operator" and a "copy constructor"



• What is the difference between "overloading" and "overridding"?



• Explain the need for "Virtual Destructor".



• Can we have "Virtual Constructors"?



• What are the different types of polymorphism?



• What are Virtual Functions? How to implement virtual functions in "C"



• What are the different types of Storage classes?



• What is Namespace?



• What are the types of STL containers?.



• Difference between "vector" and "array"?



• How to write a program such that it will delete itself after exectution?



• Can we generate a C++ source code from the binary file?



• What are inline functions?



• Talk sometiming about profiling?



• How many lines of code you have written for a single program?



• What is "strstream" ?



• How to write Multithreaded applications using C++?



• Explain "passing by value", "passing by pointer" and "passing by reference"



• Write any small program that will compile in "C" but not in "C++"



• Have you heard of "mutable" keyword?



• What is a "RTTI"?



• Is there something that I can do in C and not in C++?



• Why preincrement operator is faster than postincrement?



• What is the difference between "calloc" and "malloc"?



• What will happen if I allocate memory using "new" and free it using "free" or allocate sing "calloc" and free it using "delete"?



• What is Memory Alignment?



• Explain working of printf.



• Difference between "printf" and "sprintf".



• What is "map" in STL?



• When shall I use Multiple Inheritance?



• What are the techniques you use for debugging?



• How to reduce a final size of executable?



• Give 2 examples of a code optimization.



• What is inheritance?



• Difference between Composition and Aggregation.



• Difference: Sequence Diagrams, Collaboration Diagrams.



• Difference: 'uses', 'extends', 'includes'



• What shall I go for Package Diagram?



• What is Polymorphism?



• Is class an Object? Is object a class?



• Comment: C++ "includes" behavior and java "imports"



• What do you mean by "Realization"?



• What is a Presistent, Transient Object?



• What is the use of Operator Overloading?



• Does UML guarantee project success?



• Difference: Activity Diagram and Sequence Diagram.



• What is association?



• How to resolve many to many relationship?



• How do you represent static members and abstract classes in Class Diagram?



• 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[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 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?



• What is an object?



• What is the difference between an object and a class?



• What is the difference between class and structure?



• What is public, protected, private?



• What are virtual functions?



• What is friend function?



• What is a scope resolution operator?



• What do you mean by inheritance?



• What is abstraction?



• What is polymorphism? Explain with an example.



• What is encapsulation?



• What do you mean by binding of data and functions?



• What is function overloading and operator overloading?



• What is virtual class and friend class?



• What do you mean by inline function?



• What do you mean by public, private, protected and friendly?



• When is an object created and what is its lifetime?



• What do you mean by multiple inheritance and multilevel inheritance? Differentiate between them.



• Difference between realloc() and free?



• What is a template?



• What are the main differences between procedure oriented languages and object oriented languages?



• What is R T T I ?



• What are generic functions and generic classes?



• What is namespace?



• What is the difference between pass by reference and pass by value?



• Why do we use virtual functions?



• What do you mean by pure virtual functions?



• What are virtual classes?



• Does c++ support multilevel and multiple inheritance?



• What are the advantages of inheritance?



• When is a memory allocated to a class?



• What is the difference between declaration and definition?



• What is virtual constructors/destructors?



• In c++ there is only virtual destructors, no constructors. Why?



• What is late bound function call and early bound function call? Differentiate.



• How is exception handling carried out in c++?



• When will a constructor executed?



• What is Dynamic Polymorphism?



• Write a macro for swapping integers.