A program reads a CSV file with fgets() storing data in a 256-byte buffer. Some lines exceed 255 characters. How should this be handled?

The correct answer is A: Use larger buffer size for each fgets() call. Best solution is allocate larger buffer. If line is 500 chars, use buffer >= 501. Option C partially works but complicates newline handling. fscanf() doesn't automatically handle long lines.

What will be the output of this code? int *p = (int*)malloc(5 * sizeof(int)); printf("%d", sizeof(p));

The correct answer is B: 4 (or 8 on 64-bit systems). sizeof(p) returns the size of pointer itself (4 bytes on 32-bit, 8 bytes on 64-bit), not the allocated memory.

Which function is used to read a string from a file, including whitespace characters, up to a maximum length?

The correct answer is B: fgets(). fgets() reads a string from file including whitespace until newline or EOF is encountered or max length is reached.

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

The correct answer is B: calloc() initializes allocated memory to zero; malloc() does not. calloc() takes two parameters (count, size) and initializes memory to 0, while malloc() takes one parameter and leaves memory uninitialized.

A pointer variable stores the _____ of another variable.

The correct answer is B: memory address. Pointers store memory addresses of variables. The address-of operator (&) retrieves this address.

Home

Home › Subjects › C Programming › Basics & Syntax

C Programming
Basics & Syntax

C language from basics to advanced placement prep

19 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–10 of 19

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.1 Hard Basics & Syntax

Consider the following declaration:
int (*func_ptr)(int, int, int);
Which of the following function signatures can be correctly assigned to func_ptr?

A int add(int x, int y, int z) { return x+y+z; }

B int add(int x, int y) { return x+y; }

C void add(int x, int y, int z) { }

D float add(int x, int y, int z) { return x+y+z; }

Correct Answer: A. int add(int x, int y, int z) { return x+y+z; }

EXPLANATION

func_ptr must point to a function that takes exactly 3 int parameters and returns int. Only option A matches this signature exactly.

Test

Q.2 Hard Basics & Syntax

Which of the following correctly uses memcpy()?

A memcpy(dest, src, strlen(src));

B memcpy(dest, src, sizeof(src));

C memcpy(&dest, &src, count);

D memcpy(dest, src, count);

Correct Answer: D. memcpy(dest, src, count);

EXPLANATION

memcpy(dest, src, count) copies 'count' bytes from src to dest. strlen() and sizeof() may not give correct results for all data types.

Test

Q.3 Hard Basics & Syntax

What is the output of: float x = 5/2; printf("%f", x);

A 2.5

B 2.0

C 2.500000

D Error

Correct Answer: B. 2.0

EXPLANATION

5/2 is integer division (not float division), so result is 2 (integer), then converted to 2.0 (float).

Test

Q.4 Hard Basics & Syntax

Which of the following about function pointers in C is correct?

A int *func();

B int (*func)();

C int func*();

D int *func*();

Correct Answer: B. int (*func)();

EXPLANATION

int (*func)(); declares a pointer to a function that returns int. Option A declares a function returning pointer to int.

Test

Q.5 Hard Basics & Syntax

What will be the output of: int a = 1; int b = 2; a = a + b; b = a - b; a = a - b; printf("%d %d", a, b);

A 1 2

B 2 1

C 3 1

D 1 3

Correct Answer: B. 2 1

EXPLANATION

Initial: a=1, b=2. After step 1: a=3, b=2. After step 2: a=3, b=1. After step 3: a=2, b=1. Output is '2 1'.

Test

Q.6 Hard Basics & Syntax

What is the scope of a variable declared inside a block with 'static'?

A Global scope

B Function scope

C Block scope with static storage duration

D File scope

Correct Answer: C. Block scope with static storage duration

EXPLANATION

A static variable declared in a block has block scope but static storage duration, persisting between function calls.

Test

Q.7 Hard Basics & Syntax

What is the output of: int x = 5; int y = ++x + x++;

A y = 12

B y = 13

C Undefined behavior

D Compilation error

Correct Answer: C. Undefined behavior

EXPLANATION

This involves undefined behavior due to modification of x multiple times without intervening sequence points.

Test

Q.8 Hard Basics & Syntax

What is the result of: int x = 10; int y = x++ + x++;

A y = 20

B y = 21

C y = 22

D Undefined behavior

Correct Answer: D. Undefined behavior

EXPLANATION

Multiple post-increments without sequence points lead to undefined behavior.

Test

Q.9 Hard Basics & Syntax

What will be the output of: int x = 5; printf("%d", x++ + ++x);

A 11

B 12

C 10

D Undefined behavior

Correct Answer: D. Undefined behavior

EXPLANATION

This exhibits undefined behavior due to multiple modifications of the same variable 'x' without intervening sequence points.

Test

Q.10 Hard Basics & Syntax

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

A Guarantees storage in CPU register

B A hint to the compiler to optimize variable storage; compiler may ignore it

C Forces the variable to be global

D Automatically allocates memory on the stack

Correct Answer: B. A hint to the compiler to optimize variable storage; compiler may ignore it

EXPLANATION

The 'register' keyword is a hint for compiler optimization. Modern compilers often ignore it as they have sophisticated optimization strategies.

Test

1 2

All Subjects & Topics

Govt. Exams

Entrance Exams

Teacher Exams

Subjects

Quick Links

C Programming Basics & Syntax

C Programming
Basics & Syntax