Which of the following correctly demonstrates the use of conditional compilation?

The correct answer is A: #ifdef DEBUG printf("Debug mode"); #endif. Option A uses #ifdef to check if DEBUG is defined, which is correct for conditional compilation. Option B would check if DEBUG has a non-zero value (expression-based). Options C and D have invalid syntax.

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.

A program writes data using fprintf() and later attempts to read it back. However, the read operation fails intermittently. What could be the most likely cause?

The correct answer is B: The buffer was not flushed before reading, causing incomplete data. fprintf() buffers output. Without flushing (fflush() or fclose()), subsequent read operations may see incomplete data. This is a common source of bugs.

What is the range of values for 'signed char' in C (assuming 8-bit char)?

The correct answer is B: -128 to 127. A signed char is 1 byte (8 bits) and can represent values from -128 to 127 using two's complement representation.

What will be the result of the bitwise operation: 5 & 3 in C?

The correct answer is A: 1. 5 (binary 101) & 3 (binary 011) = 001 (binary) = 1. Bitwise AND operates on each bit position.

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C Programming
Functions

C language from basics to advanced placement prep

47 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 41–47 of 47

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.41 Medium Functions

In C, are function parameters passed by value or by reference by default?

A By value

B By reference

C Depends on the data type

D Both simultaneously

Correct Answer: A. By value

EXPLANATION

C passes parameters by value by default. To achieve pass-by-reference effect, pointers must be used explicitly.

Test

Q.42 Medium Functions

What is the issue with the following code?
int factorial(int n) { return n * factorial(n-1); }

A Syntax error

B No base case, leading to infinite recursion and stack overflow

C The function cannot call itself

D Missing return type

Correct Answer: B. No base case, leading to infinite recursion and stack overflow

EXPLANATION

The recursive function lacks a base case (like if n==0 return 1) to terminate recursion, causing infinite recursion and stack overflow.

Test

Q.43 Medium Functions

What is a recursive function?

A A function that calls itself directly or indirectly

B A function that calls another function

C A function that returns multiple values

D A function that has no parameters

Correct Answer: A. A function that calls itself directly or indirectly

EXPLANATION

A recursive function is one that calls itself. It must have a base case to avoid infinite recursion.

Test

Q.44 Medium Functions

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

A calculate(5, 3.14, 'A');

B calculate(5);

C calculate(5, 3.14);

D calculate('A', 3.14, 5);

Correct Answer: A. calculate(5, 3.14, 'A');

EXPLANATION

All three parameters must be provided in correct order and compatible types.

Test

Q.45 Medium Functions

What happens if a function does not have a return statement?

A Compilation error occurs

B Runtime error occurs

C An undefined/garbage value is returned

D 0 is returned by default

Correct Answer: C. An undefined/garbage value is returned

EXPLANATION

If a function with a non-void return type lacks a return statement, it returns undefined/garbage value. For void functions, no return is needed.

Test

Q.46 Medium Functions

What is the difference between function declaration and function definition?

A Declaration provides the function prototype; definition provides the actual implementation

B They are the same thing

C Declaration is mandatory; definition is optional

D Definition comes before declaration always

Correct Answer: A. Declaration provides the function prototype; definition provides the actual implementation

EXPLANATION

Declaration (prototype) tells the compiler about the function signature; definition provides the actual function body and implementation.

Test

Q.47 Medium Functions

What is the default return type of a function in C if not specified?

A void

B int

C float

D char

Correct Answer: B. int

EXPLANATION

In older C standards (before C99), if no return type is specified, the default is 'int'. However, this is deprecated in modern C standards.

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