Top 130 C Programming Interview Questions 2019 | Mock Interview practice.

C Programming Language

The C programming language is a popular and widely used programming language for creating computer programs. The main feature of C language includes low-level access to memory, a simple set of keywords, and clean style these features make C language more suitable for system programmings like operating system and compiler development.

If you are a programmer, or if you are interested in becoming a programmer then C language is one of the powerful languages with features like reliability, portability, flexibility, interactivity, modularity, efficiency and effectiveness.

C Programming Language Interview Questions

1. What are bit fields in C?
2. List some applications of C programming language?
3. What is the difference between a constant pointer and a constant variable?
4. Compare array data type to pointer data type
5. Differentiate call by value and call by reference?
6. What is the best way to store flag values in a program?
7. What do you understand by normalization of pointers?
8. When can you use a pointer with a function?
9. What is a structure in C Language.How to initialise a structure in C?
10. If the size of int data type is two bytes, what is the range of signed int data type?
11. When can a far pointer be used?
12. Explain Enumerated types in C language?
13. What is a scope resolution operator in C?
14. Explain bit masking in C?
15. What are Derived data types in C?
16. What are static variables in C?
17. What is the register variable in C language?
18. Is there any data type in C with variable size?
19. What is recursion in C?
20. Is there any demerits of using pointer?
21. Explain about block scope in C?
22. What are different storage class specifiers in C
23. What does paintf do?
24. Explain the main function in C?
25. How can you find the exact size of a data type in C?
26. Explain C preprocessor?
27. What is the difference between structure and union?
28. Explain Pointers in C programming?
29. What is the difference between #include <header file> and #include “header file” ?
30. What is a NULL pointer?
31. What is the use of extern in C?
32. What is an auto variable in C?
33. What is a void pointer?
34. Explain continue keyword in C
35. List some basic data types in C?
36. What is a pointer on pointer?
37. Distinguish between malloc() & calloc() memory allocation.
38. What is keyword auto for?
39. What are the valid places for the keyword break to appear?
40. Explain the syntax for loop.
41. What is the difference between including the header file with-in angular braces < > and double quotes “ “
42. How a negative integer is stored.
43. What is a static variable?
44. What is a NULL pointer?
45. What is the purpose of extern storage specifier?
46. Explain the purpose of the function sprintf().
47. What is the meaning of base address of the array?
48. When should we use the register storage specifier?
49. S++ or S = S+1, which can be recommended to increment the value by 1 and why?
50. What is a dangling pointer?
51. What is the purpose of the keyword typedef?
52. What is lvalue and rvalue?
53. What is the difference between actual and formal parameters?
54. Can a program be compiled without main() function?
55. What is the advantage of declaring void pointers?
56. Where an automatic variable is stored?
57. What is a nested structure?
58. What is the difference between variable declaration and variable definition?
59. What is a self-referential structure?
60. Does a built-in header file contains built-in function definition?
61. Explain modular programming.
62. What is a token?
63. What is a preprocessor?
64. Explain the use of %i format specifier w.r.t scanf().
65. How can you print a \ (backslash) using any of the printf() family of functions.
66. Does a break is required by default case in switch statement?
67. When to user -> (arrow) operator.
68. What are bit fields?
69. What are command line arguments?
70. What are the different ways of passing parameters to the functions? Which to use when?
71. What is the purpose of built-in stricmp() function.
72. Describe the file opening mode “w+”.
73. Where the address of operator (&) cannot be used?
74. Is FILE a built-in data type?
75. What is reminder for 5.0 % 2?
76. How many operators are there under the category of ternary operators?
77. Which key word is used to perform unconditional branching?
78. What is a pointer to a function? Give the general syntax for the same.
79. Explain the use of comma operator (,).
80. What is a NULL statement?
81. What is a static function?
82. Which compiler switch to be used for compiling the programs using math library with gcc compiler?
83. Which operator is used to continue the definition of macro in the next line?
84. Which operator is used to receive the variable number of arguments for a function?
85. What is the problem with the following coding snippet?
86. Which built-in library function can be used to re-size the allocated dynamic memory?
87. Define an array.
88. What are enumerations?
89. Which built-in function can be used to move the file pointer internally?
90. What is a variable?
91. Who designed C programming language?
92. C is successor of which programming language?
93. What is the full form of ANSI?
94. Which operator can be used to determine the size of a data type or variable?
95. Can we assign a float variable to a long integer variable?
96. Is 068 a valid octal number?
97. What it the return value of a relational operator if it returns any?
98. How does bitwise operator XOR works.
99. What is an infinite loop?
100. Can variables belonging to different scope have same name? If so show an example.
101. What is the default value of local and global variables?
102. Can a pointer access the array?
103. What are valid operations on pointers?
104. What is a string length?
105. What is the built-in function to append one string to another?
106. Which operator can be used to access union elements if union variable is a pointer variable?
107. Explain about ‘stdin’.
108. Name a function which can be used to close the file stream.
109. What is the purpose of #undef preprocessor?
110. Define a structure.
111. Name the predefined macro which be used to determine whether your compiler is ANSI standard or not?
112. What is typecasting?
113. What is recursion?
114. Which function can be used to release the dynamic allocated memory?
115. What is the first string in the argument vector w.r.t command line arguments?
116. How can we determine whether a file is successfully opened or not using fopen() function?
117. What is the output file generated by the linker.
118. What is the maximum length of an identifier?
119. What is the default function call method?
120. Functions must and should be declared. Comment on this.
121. When the macros gets expanded?
122. Can a function return multiple values to the caller using return reserved word?
123. What is a constant pointer?
124. To make pointer generic for which date type it need to be declared?
125. Can the structure variable be initialized as soon as it is declared?
126. Is there a way to compare two structure variables?
127. Which built-in library function can be used to match a patter from the string?
128. What is difference between far and near pointers?
129. Can we nest comments in a C code?
130. Which control loop is recommended if you have to execute set of statements for fixed number of times?
131. What is a constant?
132. Can we use just the tag name of structures to declare the variables for the same?
133. Can the main() function left empty?
134. Can one function call another?