What will be the output of fseek(fp, -10, SEEK_END) in a file of 100 bytes?

The correct answer is A: File pointer moves to byte 90. fseek(fp, -10, SEEK_END) positions the pointer 10 bytes before the end of file. For a 100-byte file, this places it at position 90 (0-indexed). Negative offsets with SEEK_END are valid.

In a structure, what does the #pragma pack(1) directive do?

The correct answer is A: Removes padding between members. #pragma pack(1) removes padding, making members occupy consecutive memory locations for compact storage.

In implementing a dynamic doubly-linked list, what additional field is required compared to singly-linked list?

The correct answer is B: Previous pointer. Doubly-linked list nodes require both next and previous pointers to enable bidirectional traversal unlike singly-linked lists.

Which of the following correctly demonstrates self-referential structure (for linked list)?

The correct answer is A: struct Node { int data; struct Node *next; };. In C, self-referential structures require the struct keyword in pointer declarations within the structure definition.

What is the output? int x = 5; int *const p = &x; x = 10; printf("%d", *p);

The correct answer is B: 10. const pointer p cannot be changed, but x can be modified. *p prints current value of x which is 10.

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C Programming

C language from basics to advanced placement prep

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Difficulty: All Easy Medium Hard 231–240 of 490

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.231 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.232 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.233 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.234 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.235 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.236 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.237 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.238 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.239 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

Q.240 Medium Pointers

Consider the code: int arr[] = {5, 10, 15, 20}; int *ptr = arr; ptr++; What does ptr now point to?

A The value 5

B The value 10

C The address of arr[1]

D The address increased by 1 byte

Correct Answer: C. The address of arr[1]

EXPLANATION

Pointer arithmetic increments by the size of the data type. For int (4 bytes), ptr++ moves to the next integer, which is arr[1].

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