Pointer - C Programming MCQ Questions and Answers

11

What is the result of the expression &variable in C, where variable is a variable of type int?

A) Address of variable B) Value of variable C) Size of variable D) Type of variable

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Answer & Solution

Answer: Option A

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12

In C, what is a double pointer (int**)?

A) A pointer to an integer B) A pointer that can store two addresses C) A pointer to a pointer D) A pointer to a double data type

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Answer & Solution

Answer: Option C

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13

What is the result of the expression ptr = NULL in C, where ptr is a pointer?

A) Initialize ptr to 0 B) Delete the pointer ptr C) Set ptr to a random address D) It's not a valid operation

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Answer & Solution

Answer: Option A

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14

In C, what is the purpose of the 'malloc' function?

A) Allocate memory on the stack B) Allocate memory on the heap C) Allocate memory for a function D) Allocate memory for a variable

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Answer & Solution

Answer: Option B

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15

What is the result of the expression *NULL in C?

A) Error B) Null pointer dereference C) 0 D) Undefined

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Answer & Solution

Answer: Option A

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16

In C, what is the purpose of the 'memcpy' function?

A) Copy the contents of one pointer to another B) Copy the contents of one memory location to another C) Create a new pointer D) Swap two pointers

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Answer & Solution

Answer: Option B

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17

What is the result of the expression sizeof(char*) in C, assuming a char pointer on a typical system?

A) 4 B) 8 C) 2 D) 1

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Answer & Solution

Answer: Option A

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18

In C, how do you declare an array of pointers to integers?

A) int* arr[]; B) arr int*[]; C) int arr*[]; D) int[]* arr;

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Answer & Solution

Answer: Option A

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19

What is the purpose of the 'free' function in C when used with pointers?

A) Allocate memory B) Deallocate memory C) Create a new pointer D) Modify the pointer's value

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Answer & Solution

Answer: Option B

Solution:

The 'free' function in C is used to deallocate memory that was previously allocated using functions like malloc, calloc, or realloc.

When memory is allocated dynamically, it resides in the heap, and it is the programmer's responsibility to release that memory when it is no longer needed.

Using 'free' helps prevent memory leaks by returning the allocated memory back to the system.

Option A is incorrect because allocating memory is done using malloc, calloc, or realloc.

Option C is incorrect because 'free' does not create new pointers.

Option D is incorrect because 'free' does not modify the value of the pointer; it only releases the memory the pointer points to.

Therefore, the correct answer is Option B: Deallocate memory.

20

In C, what is a pointer to a constant value (const int*)?

A) A pointer that cannot be modified B) A pointer that points to a constant value C) A constant pointer D) A pointer to a constant value

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Answer & Solution

Answer: Option D

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