What is the primary issue with this code? int *p; *p = 10;

The correct answer is B: Pointer p is uninitialized and points to garbage memory. p is declared but not initialized to point to any valid memory location. Dereferencing an uninitialized pointer causes undefined behavior.

Which approach correctly implements a file copy function for both text and binary files?

The correct answer is D: Binary copy is sufficient for all file types. Binary mode works for all files because it's just byte-for-byte copy. Text mode conversions are unnecessary for copying.

Which of the following best describes the 'register' storage class in modern C compilers?

The correct answer is B: A hint to the compiler to optimize variable storage; compiler may ignore it. The 'register' keyword is a hint for compiler optimization. Modern compilers often ignore it as they have sophisticated optimization strategies.

What is the key distinction between if-else and switch statements in terms of evaluation?

The correct answer is B: if-else evaluates conditions, switch uses jump table for integral constants. switch typically uses jump tables for efficient multi-way branching with integral values, while if-else evaluates boolean expressions sequentially.

Which of the following statements about NULL is correct?

The correct answer is D: Both B and C. NULL is a macro (not a keyword) typically defined as (void *)0, and can be used interchangeably with 0 for pointer assignments.

Home

Home › Subjects › C Programming › Pointers

C Programming
Pointers

C language from basics to advanced placement prep

51 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 31–40 of 51

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.31 Medium Pointers

What does calloc() do that malloc() doesn't?

A Allocates more memory

B Initializes allocated memory to zero

C Allocates memory faster

D Returns a void pointer

Correct Answer: B. Initializes allocated memory to zero

EXPLANATION

calloc() takes two parameters (number of elements, size) and initializes all bytes to zero, while malloc() leaves memory uninitialized.

Test

Q.32 Medium Pointers

What will be the output?
int a[] = {10, 20, 30};
int *p = a;
printf("%d", *(p+2));

A 10

B 20

C 30

D Garbage value

Correct Answer: C. 30

EXPLANATION

p points to a[0], p+2 points to a[2] which contains 30. Dereferencing gives 30.

Test

Q.33 Medium Pointers

What is the difference between pointer and array name in C?

A No difference, both are same

B Array name is a pointer constant, cannot be modified

C Pointer can store any address, array name stores only array address

D Arrays are faster than pointers

Correct Answer: B. Array name is a pointer constant, cannot be modified

EXPLANATION

Array names are pointer constants that point to the first element and cannot be reassigned, while pointer variables can be modified to point to different addresses.

Test

Q.34 Medium Pointers

What will be the output of: int x = 10; int *p = &x; printf("%p", p); (assuming typical system output)

A 10

B A memory address in hexadecimal format

C The size of integer

D Error: invalid format specifier

Correct Answer: B. A memory address in hexadecimal format

EXPLANATION

The %p format specifier prints the pointer value as a memory address in hexadecimal format, not the dereferenced value.

Test

Q.35 Medium Pointers

Consider: void func(int *arr, int size); This function prototype suggests that func will:

A Create a new array inside the function

B Modify the original array passed from the caller

C Only read the array values

D Return the array to the caller

Correct Answer: B. Modify the original array passed from the caller

EXPLANATION

Since an array pointer is passed, the function can access and modify the original array elements in the caller's scope.

Test

Q.36 Medium Pointers

A function needs to modify a variable in the calling function. Which parameter passing method is appropriate?

A Pass by value

B Pass by reference using pointers

C Pass by global variable

D None of the above

Correct Answer: B. Pass by reference using pointers

EXPLANATION

To modify a variable in the calling function, you must pass its address (pointer). Pass by value creates a copy and cannot modify the original.

Test

Q.37 Medium Pointers

Consider: int arr[5] = {1, 2, 3, 4, 5}; int *p = arr; What is the value of *(p+2)?

A 2

B 3

C 4

D 5

Correct Answer: B. 3

EXPLANATION

p points to arr[0]. p+2 points to arr[2], and *(p+2) dereferences to the value at arr[2], which is 3.

Test

Q.38 Medium Pointers

Which memory allocation function does NOT initialize allocated memory to zero?

A calloc()

B malloc()

C realloc()

D Both B and C

Correct Answer: D. Both B and C

EXPLANATION

malloc() and realloc() return uninitialized memory with garbage values. calloc() initializes all bytes to zero.

Test

Q.39 Medium Pointers

Consider: int x = 5; int *p = &x; int **q = &p; What is the value of **q?

A 5

B Address of p

C Address of x

D Error

Correct Answer: A. 5

EXPLANATION

q is a pointer to pointer p. **q dereferences twice: first to get p, then to get the value x, which is 5.

Test

Q.40 Medium Pointers

Which of the following best describes a dangling pointer situation?

A A pointer that points to a valid memory location

B A pointer that points to memory that has been freed or deallocated

C A pointer that has not been initialized

D A pointer used in arithmetic operations

Correct Answer: B. A pointer that points to memory that has been freed or deallocated

EXPLANATION

A dangling pointer occurs when it points to memory that no longer exists, typically after free() or when a local variable goes out of scope.

Test

1 2 3 4 5 6

All Subjects & Topics

Govt. Exams

Entrance Exams

Teacher Exams

Subjects

Quick Links

C Programming Pointers

C Programming
Pointers