Top 50 C, C++ Interview Questions asked in Interviews!

1. What does static variable mean?
2. What is a pointer?
3. What is a structure?
4. What are enumerations?
5. Describe about storage allocation and scope of global, extern, static, local and register variables?
6. What are register variables? What are the advantage of using register variables?
7. What is difference between Structure and Unions?
8. What the advantages of using Unions?
9. What are the advantages of using pointers in a program?
10. What is the difference between Strings and Arrays?
11. In a header file whether functions are declared or defined?
12. What is a far pointer? where we use it?
13. How will you declare an array of three function pointers where each function receives two ints and returns a float?
14. What is a NULL Pointer? Whether it is same as an uninitialized pointer?
15. What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?
16. What does the error ‘Null Pointer Assignment’ mean and what causes this error?
17. What is near, far and huge pointers? How many bytes are occupied by them?
18. How would you obtain segment and offset addresses from a far address of a memory location?
19. 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?
20. Does there exist any way to make the command line arguments available to other functions without passing them as arguments to the function?
21. What are bit fields? What is the use of bit fields in a Structure declaration?
22. To which numbering system can the binary number 1101100100111100 be easily converted to?
23. Which bit wise operator is suitable for checking whether a particular bit is on or off?
24. Which bit wise operator is suitable for turning off a particular bit in a number?
25. Which bit wise operator is suitable for putting on a particular bit in a number?
26. Which bit wise operator is suitable for checking whether a particular bit is on or off?
27. Which header file should you include if you are to develop a function which can accept variable number of arguments?
28. Can you write a function similar to printf()?
29. How can a called function determine the number of arguments that have been passed to it?
30. Can there be at least some solution to determine the number of arguments passed to a variable argument list function?
31. How would you use the functions sin(), pow(), sqrt()?
32. How would you use the functions memcpy(), memset(), memmove()?
33. How would you use the functions fseek(), freed(), fwrite() and ftell()?
34. How would you obtain the current time and difference between two times?
35. How would you use the functions randomize() and random()?
36. How would you implement a substr() function that extracts a sub string from a given string?
37. What is the difference between the functions rand(), random(), srand() and randomize()?
38. What is the difference between the functions memmove() and memcpy()?
39. How do you print a string on the printer?
40. Can you use the function fprintf() to display the output on the screen?
41. What is a linklist and why do we use it when we have arrays? - I feel the correct answer should be linklist is used in cases where you don’t know the memory required to store a data structure and need to allocate is dynamically on demand.
42. How do you detect a loop in linked list?
43. What is the difference between main() in C and main() in C++?
44. what will be printed out when the following code is executed:
    

    main()
    {
    printf("%x",-1<<4);
    }

45. In header files whether functions are declared or defined?
46. What are the differences between malloc() and calloc()?
47. What are macros? What are the advantages and disadvantages?
48. Difference between pass by reference and pass by value?
49. What is static identifier?
50. Where are the auto variables stored?