What will be printed by: int arr[3] = {1, 2, 3}; printf("%d", *(arr + 1));

The correct answer is B: 2. arr + 1 points to the second element, so *(arr + 1) dereferences it to give 2.

When implementing a log file writer with concurrent access, what's the critical issue with standard fopen()?

The correct answer is B: No built-in file locking mechanism. Standard C fopen/fwrite lack file locking. Multiple processes can corrupt data. Need OS-specific locking (flock/fcntl on Unix) or use 'a' mode with small writes.

Which of the following correctly declares a function pointer that points to a function returning int and taking two int parameters?

The correct answer is A: int (*funcPtr)(int, int);. The correct syntax for function pointer is return_type (*pointer_name)(parameter_types). Option A is correct.

What will be the output of this code? union Data { int x; char y; }; Data d = {65}; d.y = 'A'; printf("%d", d.x);

The correct answer is D: Undefined behavior. Modifying y changes the same memory location as x. Only the last byte of x is affected, leading to unpredictable output.

Which of the following function calls is valid? int calculate(int a, float b, char c);

The correct answer is A: calculate(5, 3.14, 'A');. All three parameters must be provided in correct order and compatible types.

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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 131–140 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.131 Easy Pointers

What does the & operator do when used with a variable?

A Returns the value of the variable

B Returns the address of the variable

C Creates a copy of the variable

D Deallocates memory

Correct Answer: B. Returns the address of the variable

EXPLANATION

The & (address-of) operator returns the memory address of the variable.

Test

Q.132 Easy Pointers

What is the size of a pointer variable in a 64-bit system?

A 8 bytes

B 4 bytes

C Depends on data type

D 16 bytes

Correct Answer: A. 8 bytes

EXPLANATION

In a 64-bit system, all pointers occupy 8 bytes regardless of the data type they point to.

Test

Q.133 Easy Pointers

What will be printed by the code: char *ptr = "Hello"; printf("%c", *ptr);

A H

B Hello

C e

D Error

Correct Answer: A. H

EXPLANATION

ptr points to the first character of the string, so *ptr dereferences to 'H'. The %c format specifier prints a single character.

Test

Q.134 Easy Pointers

Which operator is used to get the address of a variable?

A * (asterisk)

B & (ampersand)

C -> (arrow)

D . (dot)

Correct Answer: B. & (ampersand)

EXPLANATION

The & (address-of) operator returns the memory address of a variable.

Test

Q.135 Easy Pointers

Consider: int x = 10; int *p = &x; What does the expression *p represent?

A The address of x

B The pointer variable p

C The value stored in x

D The size of x

Correct Answer: C. The value stored in x

EXPLANATION

The dereference operator (*) accesses the value at the address pointed to by p, which is the value 10.

Test

Q.136 Easy Pointers

What is the size of a pointer variable on a 32-bit system?

A 2 bytes

B 4 bytes

C 8 bytes

D Depends on the data type

Correct Answer: B. 4 bytes

EXPLANATION

On a 32-bit system, all pointers are 4 bytes (32 bits) regardless of the data type they point to.

Test

Q.137 Easy Pointers

A pointer variable stores the _____ of another variable.

A value

B memory address

C data type

D size

Correct Answer: B. memory address

EXPLANATION

Pointers store memory addresses of variables. The address-of operator (&) retrieves this address.

Test

Q.138 Easy Pointers

Identify the output:
char *str = "Hello";
printf("%c", *str);

A H

B Hello

C e

D Address

Correct Answer: A. H

EXPLANATION

*str dereferences the pointer to get the first character of the string, which is 'H'.

Test

Q.139 Easy Pointers

Which of the following is NOT a valid pointer declaration?

A int *p;

B float *q;

C void *r;

D int &s;

Correct Answer: D. int &s;

EXPLANATION

& is a reference operator used in C++, not in C. In C, pointers are declared using *.

Test

Q.140 Easy Pointers

What is a NULL pointer?

A Pointer pointing to address 0

B Uninitialized pointer

C Pointer with no name

D Invalid pointer

Correct Answer: A. Pointer pointing to address 0

EXPLANATION

A NULL pointer is a pointer that points to memory address 0, indicating it doesn't point to any valid memory location.

Test

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