C Interview Questions

1.     What does static variable mean?
2.     What is a pointer?
3.     What is a structure?
4.     What are the differences between structures and arrays?
5.     In header files whether functions are declared or defined?
6.     What are the differences between malloc() and calloc()?
7.     What are macros? what are its advantages and disadvantages?
8.     Difference between pass by reference and pass by value?
9.     What is static identifier?
10.     Where are the auto variables stored?
11.     Where does global, static, local, register variables, free memory and C Program instructions get stored?
12.     Difference between arrays and linked list?
13.     What are enumerations?
14.     What is the keyword 'extern' means?
15.     What are register variables? What are the advantage of using register variables?
16.     What is the use of typedef?
17.     What is recursion?
18.     What are the different storage classes in C?
19.     What is difference between Structure and Unions?
20.     What the advantages of using Unions?
21.     What are the advantages of using pointers in a program?
22.     What is the difference between Strings and Arrays?
23.     what is a NULL Pointer? Whether it is same as an uninitialized pointer?
24.     What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?
25.     What does the error 'Null Pointer Assignment' mean and what causes this error?
26.     How can we check whether the contents of two structure variables are same or not?
27.     How are Structure passing and returning implemented by the complier?
28.     How can we read/write Structures from/to data files?
29.     What is the difference between an enumeration and a set of pre-processor # defines?
30.     What are bit fields? What is the use of bit fields in a Structure declaration?
31.     Which bit wise operator is suitable for checking whether a particular bit is on or off?
32.     Which bit wise operator is suitable for turning off a particular bit in a number?
33.     Which bit wise operator is suitable for putting on a particular bit in a number?
34.     Which bit wise operator is suitable for checking whether a particular bit is on or off?
35.     Write a program to compare two strings without using the strcmp() function.
36.     Write a program to concatenate two strings.
37.     Write a program to interchange 2 variables without using the third one.
38.     Write programs for String Reversal without using string functions.
39.     What are the advantages of using typedef in a program?
40.     What is the difference between the functions memmove() and memcpy()?
41.     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