C Interview Questions

1. What is C language ?
2. What does static variable mean?
3. What are the different storage classes in C ?
4. What is hashing ?
5. Can static variables be declared in a header file ?
6. Can a variable be both constant and volatile ?
7. Can include files be nested?
8. What is a null pointer ?
9. What is the output of printf("%d") ?
10. What is the difference between calloc() and malloc() ?
11. What is the difference between printf() and sprintf() ?
12. How to reduce a final size of executable ?
13. Can you tell me how to check whether a linked list is circular ?
14. Advantages of a macro over a function ?
15. What is the difference between strings and character arrays ?
16. Write down the equivalent pointer expression for referring the same element a[i][j][k][l] ?
17. Which bit wise operator is suitable for checking whether a particular bit is on or off ?
18. Which bit wise operator is suitable for turning off a particular bit in a number ?
19. Which bit wise operator is suitable for putting on a particular bit in a number ?
20. Does there exist any other function which can be used to convert an integer or a float to a string ?
21. Why does malloc(0) return valid memory address ? What's the use ?
22. Difference between const char* p and char const* p
23. What is the result of using Option Explicit ?
24. What is the benefit of using an enum rather than a #define constant ?
25. What is the quickest sorting method to use ?
26. When should the volatile modifier be used ?
27. When should the register modifier be used? Does it really help ?
28. How can you determine the size of an allocated portion of memory ?
29. What is page thrashing ?
30. When does the compiler not implicitly generate the address of the first element of an array ?
31. What is the benefit of using #define to declare a constant ?
32. How can I search for data in a linked list ?
33. Why should we assign NULL to the elements (pointer) after freeing them ?
34. What is a null pointer assignment error ? What are bus errors, memory faults, and core dumps ?
35. When should a type cast be used ?
36. What is the difference between a string copy (strcpy) and a memory copy (memcpy)? When should each be used?
37. How can I convert a string to a number ?
38. How can I convert a number to a string ?
39. Is it possible to execute code even after the program exits the main() function?
40. What is the stack ?
41. How do you print an address ?
42. Can a file other than a .h file be included with #include ?
43. What is Preprocessor ?
44. How can you restore a redirected standard stream ?
45. What is the purpose of realloc( ) ?
46. What is the heap ?
47. How do you use a pointer to a function ?
48. What is the purpose of main( ) function ?
49. Why n++ executes faster than n+1 ?
50. What will the preprocessor do for a program ?
51. What is the benefit of using const for declaring constants ?
52. What is the easiest sorting method to use ?
53. Is it better to use a macro or a function ?
54. What are the standard predefined macros ?