Top 100 C Programming MCQs with Answers 2026
Master C Programming MCQs with answers using MCQ Journey’s Top 100 C Programming MCQs with Answers 2026. This carefully curated set of multiple‑choice questions is designed to help students, professionals, and exam aspirants strengthen their understanding of core programming concepts. Covering topics such as data types, operators, control structures, functions, arrays, pointers, strings, file handling, and dynamic memory allocation, these practice questions provide a complete learning resource for exam preparation, competitive exams, university tests, and technical interviews. Each MCQ is accompanied by a clear, accurate answer to ensure effective self‑study and concept reinforcement. Ideal for candidates preparing for GATE, UGC NET, SSC, Banking exams, and placement interviews, this updated 2026 collection aligns with current exam patterns and syllabus requirements. With structured, exam‑oriented content, MCQ Journey makes learning efficient, engaging, and result‑driven. Boost your confidence and accuracy with this authoritative set of C Programming MCQs with answers tailored for success in competitive and academic exams.
Q1. Which of the following is the correct syntax to declare a pointer in C?
A. int ptr;
B. int *ptr;
C. ptr int;
D. int &ptr;
Answer: B
Explanation: The * symbol is used to declare a pointer in C.
Q2. What is the default return type of a function in C if not specified?
A. void
B. int
C. float
D. char
Answer: B
Q3. Which of the following functions is used to allocate memory dynamically in C?
A. malloc()
B. calloc()
C. realloc()
D. All of the above
Answer: D
Q4. Which header file is required for using printf() and scanf() functions?
A. stdlib.h
B. stdio.h
C. string.h
D. math.h
Answer: B
Q5. What is the size of int data type in C (on most modern compilers)?
A. 2 bytes B. 4 bytes C. 8 bytes D. Compiler dependent Answer: B
Q6. Which operator is used to access the value at the address stored in a pointer?
A. &
B. *
C. ->
D. .
Answer: B
Q8. Which keyword is used to define a constant in C?
A. const
B. static
C. final
D. constant
Answer: A
Q9. Which function is used to compare two strings in C?
A. strcmp()
B. strcpy()
C. strlen()
D. strcat()
Answer: A
Q10. Which operator has the highest precedence in C?
A. ++ (increment)
B. * (multiplication)
C. = (assignment)
D. && (logical AND)
Answer: A
Explanation: Increment and decrement operators have higher precedence than arithmetic and logical operators.
Q11. Which of the following is not a valid loop in C?
A. for
B. while
C. do-while
D. foreach
Answer: D
Q12. Which function is used to open a file in C?
A. fopen()
B. openfile()
C. fileopen()
D. open()
Answer: A
Q13. Which keyword is used to define a structure in C?
A. struct
B. class
C. object
D. union
Answer: A
Q14. Which of the following is true about recursion in C?
A. A function calling itself B. A function calling another function C. A function that cannot return a value D. A function that runs infinitely Answer: A
Q15. Which operator is used for bitwise AND in C?
A. &&
B. &
C. ||
D. |
Answer: B
Q16. Which of the following is not a valid data type in C?
A. int
B. float
C. double
D. string
Answer: D
Explanation: C does not have a string data type; strings are handled as arrays of characters.
Q17. Which function is used to find the length of a string in C?
A. strlen()
B. strlength()
C. size()
D. count()
Answer: A
Q18. Which of the following is the correct way to declare an array in C?
A. int arr[10];
B. array int arr[10];
C. int arr = [10];
D. int[10] arr;
Answer: A
Q19. Which function is used to allocate memory and initialize it to zero in C?
A. malloc()
B. calloc()
C. realloc()
D. free()
Answer: B
Q20. Which of the following is true about sizeof operator in C?
A. It returns the size of a variable or data type. B. It can be applied to functions. C. It always returns 4. D. It is invalid for arrays. Answer: A
Q21. Which keyword is used to prevent modification of a variable in C?
A. static
B. const
C. volatile
D. immutable
Answer: B
Q22. Which of the following is used to define macros in C?
A. #define
B. #macro
C. #const
D. #def
Answer: A
Q23. Which of the following is true about union in C?
A. All members share the same memory location.
B. Each member has separate memory.
C. It is identical to struct.
D. It cannot store integers.
Answer: A
Q24. Which function is used to read a single character from the keyboard in C?
A. getchar()
B. scanf()
C. gets()
D. read()
Answer: A
Q25. Which of the following is the correct format specifier for float in C?
A. %d
B. %f
C. %c
D. %lf
Answer: B
Q26. Which of the following is true about break statement in C?
A. It terminates the loop immediately. B. It skips the current iteration. C. It continues to the next iteration. D. It exits the program. Answer: A
Q27. Which function is used to close a file in C?
A. fclose()
B. closefile()
C. endfile()
D. stopfile()
Answer: A
Q28. Which of the following is the correct format specifier for float in C?
A. %d
B. %f
C. %c
D. %lf
Answer: B
Q29. Which of the following is true about break statement in C?
A. It terminates the loop immediately. B. It skips the current iteration. C. It continues to the next iteration. D. It exits the program. Answer: A
Q30. Which function is used to close a file in C?
A. fclose()
B. closefile()
C. endfile()
D. stopfile()
Answer: A
Q31. Which operator is used to access members of a structure through a pointer?
A. .
B. ->
C. *
D. &
Answer: B
Explanation: The arrow operator (->) is used with pointers to access structure members.
Q32. Which of the following is true about static variables in C?
A. They are initialized only once. B. They are reinitialized every time the function is called. C. They cannot be declared inside functions. D. They are always global. Answer: A
Q33. Which function is used to convert a string to an integer in C?
A. atoi()
B. itoa()
C. strint()
D. convert()
Answer: A
Q34. Which of the following is not a valid pointer type in C?
A. int *ptr;
B. float *ptr;
C. void *ptr;
D. string *ptr;
Answer: D
Explanation: C does not have a string type; strings are arrays of characters.
Q35. Which of the following is true about enum in C?
A. It assigns symbolic names to integral constants.
B. It is used to define floating constants.
C. It is identical to struct.
D. It cannot be used in switch statements.
Answer: A
Q36. Which function is used to copy one string into another in C?
A. strcpy()
B. strcmp()
C. strcat()
D. strlen()
Answer: A
Q37. Which of the following is true about volatile keyword in C?
A. It prevents optimization of a variable. B. It makes a variable constant. C. It initializes a variable to zero. D. It is used for dynamic memory. Answer: A
Q38. Which of the following is the correct way to declare a function prototype in C?
A. int sum(int, int);
B. sum(int, int);
C. function sum(int, int);
D. declare sum(int, int);
Answer: A
Q39. Which of the following is true about sizeof operator in C?
A. It is evaluated at compile time. B. It is evaluated at run time. C. It always returns 8. D. It cannot be used with arrays. Answer: A
Q40. Which of the following is used to free dynamically allocated memory in C?
A. delete()
B. free()
C. remove()
D. clear()
Answer: B
Q41. Which of the following is the correct way to declare a function returning a pointer in C?
A. int *func();
B. func* int();
C. pointer func();
D. int func*();
Answer: A
Q42. Which of the following is true about register variables in C?
A. They are stored in CPU registers for faster access. B. They are always global. C. They cannot be declared inside functions. D. They are initialized to zero by default. Answer: A
Q43. Which function is used to concatenate two strings in C?
A. strcat()
B. strcpy()
C. strcmp()
D. strlen()
Answer: A
Q44. Which of the following is true about goto statement in C?
A. It transfers control unconditionally to a labeled statement. B. It is used to terminate a loop. C. It is used to skip one iteration. D. It is used to exit the program. Answer: A
Q45. Which of the following is the correct format specifier for double in C?
A. %d
B. %f
C. %lf
D. %c
Answer: C
Q46. Which of the following is true about typedef in C?
A. It is used to create new data types. B. It is used to define macros. C. It is used to allocate memory. D. It is used to declare constants. Answer: A
Q47. Which function is used to write a string to a file in C?
A. fputs()
B. puts()
C. fprintf()
D. write()
Answer: A
Q48. Which of the following is true about recursion depth in C?
A. It is limited by stack size. B. It is unlimited. C. It depends on the compiler version. D. It is always 1000 calls. Answer: A
Q49. Which of the following is the correct way to declare a constant pointer in C?
A. int *const ptr;
B. const int *ptr;
C. Both A and B depending on usage.
D. constant int *ptr;
Answer: C
Explanation: int *const ptr; makes the pointer constant, while const int *ptr; makes the value constant.
Q50. Which function is used to read formatted input from a file in C?
A. fscanf()
B. scanf()
C. gets()
D. read()
Answer: A
Q51. Which of the following is true about extern keyword in C?
A. It declares a variable defined elsewhere. B. It initializes a variable to zero. C. It makes a variable constant. D. It allocates dynamic memory. Answer: A
Q52. Which function is used to write formatted output to a file in C?
A. fprintf()
B. printf()
C. fputs()
D. write()
Answer: A
Q53. Which of the following is true about sizeof operator with arrays?
A. It returns total memory occupied by the array. B. It returns the number of elements. C. It always returns 4. D. It cannot be used with arrays. Answer: A
Q54. Which of the following is used to declare a constant in C?
A. const
B. static
C. final
D. constant
Answer: A
Q55. Which function is used to seek a position in a file in C?
A. fseek()
B. seekfile()
C. position()
D. move()
Answer: A
Q56. Which of the following is true about void pointer in C?
A. It can point to any data type. B. It can only point to integers. C. It cannot be dereferenced. D. It is invalid in C. Answer: A
Q57. Which of the following is true about static functions in C?
A. They are visible only within the file they are declared. B. They are global by default. C. They cannot return values. D. They are always inline. Answer: A
Q58. Which function is used to clear the contents of a file in C?
A. Open file in write mode (w)
B. fclear()
C. reset()
D. truncate()
Answer: A
Q59. Which of the following is true about const pointer in C?
A. The pointer cannot change the value it points to. B. The pointer itself cannot change. C. Both depending on declaration. D. It is invalid in C. Answer: C
Q60. Which of the following is true about do-while loop in C?
A. It executes at least once.
B. It may not execute at all.
C. It is identical to while.
D. It cannot contain break.
Answer: A
Q61. Which function is used to allocate memory for an array in C?
A. calloc()
B. malloc()
C. realloc()
D. arrayalloc()
Answer: A
Q62. Which of the following is true about switch statement in C?
A. It can only test integers. B. It can test integers and characters. C. It can test floating values. D. It can test strings. Answer: B
Q63. Which of the following is true about continue statement in C?
A. It skips the current iteration. B. It terminates the loop. C. It exits the program. D. It transfers control to a label. Answer: A
Q64. Which function is used to open a file in append mode in C?
A. fopen("file.txt", "a")
B. openfile("file.txt", "append")
C. fileopen("file.txt", "a")
D. fopen("file.txt", "append")
Answer: A
Q65. Which of the following is true about union size in C?
A. It is equal to the size of its largest member. B. It is equal to the sum of all members. C. It is always 4 bytes. D. It is compiler dependent only. Answer: A
Q66. Which function is used to generate a random number in C?
A. rand()
B. random()
C. genrand()
D. numgen()
Answer: A
Q67. Which of the following is true about inline keyword in C?
A. It suggests compiler to replace function call with code. B. It makes function global. C. It prevents recursion. D. It allocates memory dynamically. Answer: A
Q68. Which of the following is true about sizeof(char) in C?
A. Always 1 byte. B. Always 2 bytes. C. Always 4 bytes. D. Compiler dependent. Answer: A
Q69. Which function is used to flush the output buffer in C?
A. fflush()
B. flush()
C. clear()
D. reset()
Answer: A
Q70. Which of the following is true about main() function in C?
A. It is the entry point of the program. B. It is optional. C. It can be declared multiple times. D. It cannot return values. Answer: A
Q71. Which of the following is true about sizeof operator with pointers?
A. It returns the size of the pointer itself. B. It returns the size of the value pointed. C. It always returns 8. D. It cannot be used with pointers. Answer: A
Q72. Which function is used to read a string from a file in C?
A. fgets()
B. gets()
C. scanf()
D. read()
Answer: A
Q73. Which of the following is true about dynamic memory allocation in C?
A. Memory is allocated at runtime. B. Memory is allocated at compile time. C. It is not possible in C. D. It is only possible in C++. Answer: A
Q74. Which of the following is true about sizeof(short) in C?
A. Always 2 bytes. B. Always 4 bytes. C. Always 8 bytes. D. Compiler dependent. Answer: A
Q75. Which function is used to reposition the file pointer to the beginning in C?
A. rewind()
B. reset()
C. fseek()
D. restart()
Answer: A
Q76. Which of the following is true about const keyword in function parameters?
A. It prevents modification of passed arguments. B. It initializes arguments to zero. C. It makes arguments global. D. It allocates memory dynamically. Answer: A
Q77. Which function is used to free allocated memory in C?
A. free()
B. delete()
C. clear()
D. remove()
Answer: A
Q78. Which of the following is true about sizeof(long) in C?
A. Always 4 bytes. B. Always 8 bytes. C. Compiler dependent. D. Always 2 bytes. Answer: C
Q79. Which function is used to print formatted output in C?
A. printf()
B. fprintf()
C. sprintf()
D. All of the above
Answer: D
Q80. Which of the following is true about const global variables in C?
A. They cannot be modified anywhere in the program. B. They can be modified inside functions. C. They are initialized to zero. D. They are always static. Answer: A
Q81. Which function is used to convert an integer to a string in C?
A. itoa()
B. atoi()
C. strint()
D. convert()
Answer: A
Q82. Which of the following is true about sizeof(float) in C?
A. Always 4 bytes. B. Always 8 bytes. C. Always 2 bytes. D. Compiler dependent. Answer: A
Q83. Which function is used to read formatted input in C?
A. scanf()
B. printf()
C. gets()
D. read()
Answer: A
Q84. Which of the following is true about const arrays in C?
A. Elements cannot be modified. B. Elements can be modified. C. Array size cannot be changed. D. Both A and C. Answer: D
Q85. Which function is used to write formatted output into a string in C?
A. sprintf()
B. printf()
C. fprintf()
D. puts()
Answer: A
Q86. Which of the following is true about sizeof(double) in C?
A. Always 8 bytes B. Always 4 bytes C. Always 2 bytes D. Compiler dependent Answer: A
Q87. Which function is used to compare two memory blocks in C?
A. memcmp()
B. strcmp()
C. strncmp()
D. memcpy()
Answer: A
Q88. Which of the following is true about inline functions in C?
A. They reduce function call overhead. B. They cannot return values. C. They are always recursive. D. They allocate memory dynamically. Answer: A
Q89. Which function is used to copy memory blocks in C?
A. memcpy()
B. strcpy()
C. copy()
D. memblock()
Answer: A
Q90. Which of the following is true about sizeof(void) in C?
A. It is invalid. B. It always returns 1. C. It always returns 0. D. Compiler dependent. Answer: A
Q91. Which function is used to generate pseudo-random numbers in C?
A. rand()
B. random()
C. genrand()
D. numgen()
Answer: A
Q92. Which of the following is true about volatile variables in C?
A. They can change unexpectedly, preventing optimization. B. They are constant. C. They are initialized to zero. D. They are always global. Answer: A
Q93. Which function is used to set memory blocks with a particular value in C?
A. memset()
B. memcpy()
C. strset()
D. setmem()
Answer: A
Q94. Which of the following is true about sizeof(long double) in C?
A. Usually 12 or 16 bytes depending on compiler. B. Always 8 bytes. C. Always 4 bytes. D. Always 2 bytes. Answer: A
Q95. Which function is used to read a line from a file in C?
A. fgets()
B. gets()
C. scanf()
D. readline()
Answer: A
Q96. Which of the following is true about const keyword in C?
A. It prevents modification of variables. B. It initializes variables to zero. C. It makes variables global. D. It allocates memory dynamically. Answer: A
Q97. Which function is used to reposition the file pointer in C?
A. fseek()
B. rewind()
C. reset()
D. move()
Answer: A
Q98. Which of the following is true about sizeof(short int) in C?
A. Always 2 bytes. B. Always 4 bytes. C. Always 8 bytes. D. Compiler dependent. Answer: A
Q99. Which function is used to terminate a program in C?
A. exit()
B. terminate()
C. end()
D. stop()
Answer: A
Q100. Which of the following is true about main() return value in C?
A. Returning 0 indicates successful execution. B. Returning 1 indicates success. C. Returning 0 indicates failure. D. It cannot return values. Answer: A
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