What is the range of 'signed char' in C?

The correct answer is B: -128 to 127. Signed char uses 8 bits with one bit for sign, giving range -128 to 127 (2^7 to 2^7-1).

What is the difference between 'signed' and 'unsigned' char?

The correct answer is B: Range of values they can store differs. Signed char ranges from -128 to 127, while unsigned char ranges from 0 to 255. Both use 1 byte but interpret the bits differently.

Consider a 3D array: int arr[2][3][4]. How many elements total?

The correct answer is B: 24 elements. Total elements = 2 × 3 × 4 = 24 elements in the 3D array.

In the context of function pointers, what does the restrict keyword do?

The correct answer is B: Tells the compiler that the pointer is the only way to access the data. The restrict keyword informs the compiler that the pointer is the sole means of accessing the data it points to, allowing for optimization. It's a hint for compiler optimization.

What does the 'w+' mode do when opening a file with fopen()?

The correct answer is A: Opens file for reading and writing, creates if doesn't exist. 'w+' mode opens a file for both reading and writing. If the file doesn't exist, it creates a new one. If it exists, it truncates the file to zero length.

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C Programming
Functions

C language from basics to advanced placement prep

24 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 11–20 of 24

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.11 Hard Functions

In C99 standard, what is true about function declarations at block scope?

A Functions cannot be declared inside blocks

B Function declarations inside blocks have local scope

C Such declarations are only valid with extern keyword

D Block scope declarations create implicit static storage

Correct Answer: B. Function declarations inside blocks have local scope

EXPLANATION

C99 allows function declarations within blocks; they have scope limited to that block. This is different from function definitions which remain at file scope.

Test

Q.12 Hard Functions

Analyze: int (*funcPtr)(int, int); What does this declaration represent?

A A function that takes two integers and returns pointer

B A pointer to function taking two integers returning int

C Array of function pointers

D A structure containing function pointer

Correct Answer: B. A pointer to function taking two integers returning int

EXPLANATION

The syntax (*funcPtr) indicates funcPtr is a pointer. It points to functions taking two ints and returning int.

Test

Q.13 Hard Functions

What is the correct way to return multiple values from a function in C?

A return a, b, c; // Multiple return values

B Use pointers as output parameters

C Use struct to bundle values and return struct

D Both B and C are correct approaches

Correct Answer: D. Both B and C are correct approaches

EXPLANATION

C doesn't support multiple return values. Both pointers (call-by-reference) and structs are valid techniques.

Test

Q.14 Hard Functions

Consider mutual recursion: void funcA(int n); void funcB(int n); funcA calls funcB and vice versa. What is required?

A Forward declaration of at least one function

B Both functions must be defined before any call

C Mutual recursion is not allowed in C

D Extra extern keyword for both functions

Correct Answer: A. Forward declaration of at least one function

EXPLANATION

For mutual recursion, you need forward declaration (prototype) of at least one function before it's called by another.

Test

Q.15 Hard Functions

What will happen if a recursive function has no base case?

A Compiler error

B Stack overflow at runtime

C Function returns NULL

D Infinite loop continues forever

Correct Answer: B. Stack overflow at runtime

EXPLANATION

Without base case, recursion never stops, causing stack to overflow as return addresses keep accumulating.

Test

Q.16 Hard Functions

How does the volatile keyword affect function behavior in C?

A It makes functions execute faster

B It prevents compiler optimization of variable accesses

C It changes function calling convention

D It has no effect on functions

Correct Answer: B. It prevents compiler optimization of variable accesses

EXPLANATION

The volatile keyword tells the compiler not to optimize away variable accesses, ensuring the variable is read from memory each time.

Test

Q.17 Hard Functions

What is the primary advantage of using function pointers in C?

A Faster execution than direct function calls

B Dynamic function selection at runtime

C Automatic memory management

D Better code readability

Correct Answer: B. Dynamic function selection at runtime

EXPLANATION

Function pointers enable runtime polymorphism by allowing selection of which function to call based on runtime conditions.

Test

Q.18 Hard Functions

In C99 and later standards, what is the maximum number of parameters a function can have?

A 255

B 256

C 127

D No fixed limit in standard, but implementation-dependent

Correct Answer: D. No fixed limit in standard, but implementation-dependent

EXPLANATION

While C99 guarantees support for at least 127 parameters, the actual limit is implementation-dependent and varies by compiler.

Test

Q.19 Hard Functions

What is function overloading in the context of C?

A C supports function overloading like C++

B C does not support function overloading; you must use different function names or variadic functions

C It means calling the same function multiple times

D It is a deprecated feature in modern C

Correct Answer: B. C does not support function overloading; you must use different function names or variadic functions

EXPLANATION

C does not support function overloading. To achieve similar functionality, use different names or variadic functions (using ...) or union of function pointers.

Test

Q.20 Hard Functions

Which of the following is TRUE about inline functions in C99 standard?

A They are mandatory keywords

B They are hints to the compiler to expand function code inline

C They eliminate the need for function declarations

D They cannot have parameters

Correct Answer: B. They are hints to the compiler to expand function code inline

EXPLANATION

The 'inline' keyword is a hint to the compiler to replace function calls with the function body, reducing overhead but increasing code size.

Test

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