Consider using fseek() on a file opened in text mode with SEEK_END and a non-zero offset. What is the standard behavior?

The correct answer is B: It is undefined behavior and may not work correctly on all platforms. In text mode, fseek() with non-zero offset relative to SEEK_END is undefined behavior. Use fseek(fp, 0, SEEK_END) for reliable behavior.

What is the output of: #define MULTIPLY(x,y) x*y int ans = MULTIPLY(3+2, 4+5);

The correct answer is C: 29. MULTIPLY(3+2, 4+5) expands to 3+2*4+5. Following operator precedence: 3+(2*4)+5 = 3+8+5 = 16. Actually, let me recalculate: 3+2*4+5 = 3+8+5 = 16. Hmm, that's not an option. The expansion is literally: 3+2*4+5 which equals 29 if evaluated as (3+2)*(4+5)=5*9=45. But without proper parentheses in macro

In C, what is the size of the 'char' data type?

The correct answer is B: 1 byte. By C standard, sizeof(char) is always 1 byte, regardless of platform.

What is a recursive function?

The correct answer is A: A function that calls itself directly or indirectly. A recursive function is one that calls itself. It must have a base case to avoid infinite recursion.

Which preprocessor directive is used to generate a compiler warning or error message at compile time?

The correct answer is B: #error and #pragma message. #error is standard C and generates a compilation error. #pragma message is commonly supported for warnings. #warn and #warning are non-standard. These are useful for version checking and compile-time notifications.

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C Programming

C language from basics to advanced placement prep

291 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 41–50 of 291

Topics in C Programming

All Basics & Syntax 86 Data Types & Variables 97 Control Flow 100 Functions 99 Arrays & Strings 100 Pointers 99 Structures & Unions 100 File Handling 100 Dynamic Memory 98 Preprocessor 99

Q.41 Easy Dynamic Memory

What does free() function do in C?

A Allocates memory from heap

B Deallocates previously allocated memory

C Copies memory from one location to another

D Initializes memory with zeros

Correct Answer: B. Deallocates previously allocated memory

EXPLANATION

free() is used to deallocate memory that was previously allocated using malloc(), calloc(), or realloc().

Test

Q.42 Easy Dynamic Memory

Which header file must be included to use dynamic memory allocation functions in C?

A #include

B #include

C #include

D #include

Correct Answer: A. #include

EXPLANATION

stdlib.h contains declarations for malloc(), calloc(), realloc(), and free() functions.

Test

Q.43 Easy Dynamic Memory

How much memory in bytes does calloc(10, 4) allocate?

A 10 bytes

B 4 bytes

C 40 bytes

D 10.4 bytes

Correct Answer: C. 40 bytes

EXPLANATION

calloc(num, size) allocates num * size = 10 * 4 = 40 bytes total.

Test

Q.44 Easy Dynamic Memory

What is the return type of malloc()?

A void*

B int*

C char*

D NULL

Correct Answer: A. void*

EXPLANATION

malloc() returns a generic pointer (void*) which can be cast to any data type pointer.

Test

Q.45 Easy Dynamic Memory

Which header file must be included for dynamic memory allocation functions in C?

A #include

B #include

C #include

D #include

Correct Answer: A. #include

EXPLANATION

stdlib.h contains malloc(), calloc(), realloc(), and free() functions for dynamic memory management.

Test

Q.46 Easy Dynamic Memory

What is the correct way to allocate and initialize a structure dynamically?
struct Node { int data; int next; };

A struct Node *n = malloc(sizeof(struct Node)); n->data = 5;

B struct Node *n = (struct Node*)malloc(sizeof(struct Node)); n->data = 5;

C struct Node n = malloc(sizeof(struct Node));

D Both A and B are equally correct

Correct Answer: D. Both A and B are equally correct

EXPLANATION

Both A and B allocate memory correctly; B includes explicit typecasting which is optional in C but good practice.

Test

Q.47 Easy Dynamic Memory

Which statement best describes dynamic memory allocation's advantage over static allocation?

A Dynamic memory is always faster

B Size is determined at compile time with dynamic allocation

C Memory size can be determined at runtime based on actual needs

D Dynamic memory never causes fragmentation

Correct Answer: C. Memory size can be determined at runtime based on actual needs

EXPLANATION

Dynamic memory allows flexible sizing at runtime, which static arrays cannot provide.

Test

Q.48 Easy Dynamic Memory

What happens when you call free() on a NULL pointer?

A Program crashes

B It is safely ignored (no operation performed)

C It returns false

D Undefined behavior occurs

Correct Answer: B. It is safely ignored (no operation performed)

EXPLANATION

According to C standard, free(NULL) is safe and does nothing.

Test

Q.49 Easy Dynamic Memory

What is the key difference between malloc() and calloc()?

A malloc() allocates memory; calloc() deallocates it

B calloc() initializes allocated memory to zero; malloc() does not

C malloc() is faster than calloc()

D calloc() allocates more memory than malloc()

Correct Answer: B. calloc() initializes allocated memory to zero; malloc() does not

EXPLANATION

calloc() takes two parameters (count, size) and initializes memory to 0, while malloc() takes one parameter and leaves memory uninitialized.

Test

Q.50 Easy Dynamic Memory

Which header file must be included to use malloc(), calloc(), and free() functions?

A #include

B #include

C #include

D #include

Correct Answer: B. #include

EXPLANATION

All memory allocation and deallocation functions are declared in <stdlib.h>.

Test

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