How many times will a do-while loop execute if the condition is initially false?

The correct answer is B: At least once. A do-while loop executes the body at least once before checking the condition. Even if the condition is false, the body executes one time.

What is a NULL pointer?

The correct answer is A: Pointer pointing to address 0. A NULL pointer is a pointer that points to memory address 0, indicating it doesn't point to any valid memory location.

Which of the following correctly represents a character constant in C?

The correct answer is B: 'A'. Character constants in C use single quotes ('A'). Double quotes ("") are for string literals. A single character in double quotes is a string, not a character constant.

Consider: union Data { int i; float f; char c; }; What is the size of this union?

The correct answer is A: 4 bytes. The size of a union equals the size of its largest member. Here, int is 4 bytes (largest), so union size is 4 bytes.

Which of the following is true about strcpy(dest, src)?

The correct answer is B: It copies src to dest without checking dest buffer size - potential buffer overflow. strcpy() doesn't check dest buffer size, making it unsafe. It can cause buffer overflow if src is larger than dest. Modern compilers recommend strncpy() or strlcpy().

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C Programming

C language from basics to advanced placement prep

490 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 331–340 of 490

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.331 Medium Functions

Which of the following about function declaration and definition is TRUE?

A Declaration and definition must be in the same file

B A function can be declared multiple times but defined only once

C Definition is optional if declaration is provided

D Declaration is optional in C

Correct Answer: B. A function can be declared multiple times but defined only once

EXPLANATION

Functions can have multiple forward declarations but only one definition. This allows function prototypes in header files.

Test

Q.332 Medium Functions

Which of the following correctly represents a callback function scenario?

A A function that calls itself recursively

B A function pointer passed as argument to another function

C A function that modifies global variables

D A function declared with extern keyword

Correct Answer: B. A function pointer passed as argument to another function

EXPLANATION

A callback function is a function pointer passed to another function, which calls it at a later point in time.

Test

Q.333 Medium Functions

What happens if a function declared as returning int doesn't contain a return statement?

A Compiler error

B Returns 0 by default

C Returns undefined/garbage value

D Depends on the compiler implementation

Correct Answer: C. Returns undefined/garbage value

EXPLANATION

Without an explicit return statement, the function returns whatever value is in the return register, which is undefined behavior.

Test

Q.334 Medium Functions

Which of the following is true about a static function in C?

A It cannot be called from other files

B It has only one instance throughout the program

C It is stored in static memory segment

D All of the above

Correct Answer: A. It cannot be called from other files

EXPLANATION

A static function has file scope and cannot be accessed from other translation units, providing encapsulation.

Test

Q.335 Medium Functions

What is the correct way to declare a function that accepts variable number of arguments?

A void func(...);

B void func(int, ...);

C void func(int n, ...);

D Both B and C are correct

Correct Answer: D. Both B and C are correct

EXPLANATION

Variadic functions require at least one named parameter before the ellipsis. Both options B and C follow the correct syntax.

Test

Q.336 Medium Functions

What will be printed by this code?
void func(int arr[10]) { printf("%lu", sizeof(arr)); }
int main() { int a[10]; func(a); }

A 40

B 10

C 8 (or 4 on 32-bit)

D Compiler error

Correct Answer: C. 8 (or 4 on 32-bit)

EXPLANATION

When arrays are passed to functions, they decay to pointers. sizeof(arr) returns the size of the pointer, not the array.

Test

Q.337 Medium Functions

In C, when a function is called with fewer arguments than declared, what happens?

A Compiler error occurs

B Runtime error occurs

C Garbage values are passed for missing arguments

D It compiles and runs without error if using old-style declarations

Correct Answer: D. It compiles and runs without error if using old-style declarations

EXPLANATION

Old-style K&R C declarations don't perform argument checking, allowing calls with fewer arguments. Modern prototyped functions generate compiler errors.

Test

Q.338 Medium Functions

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

A int (*funcPtr)(int, int);

B int *funcPtr(int, int);

C funcPtr *int(int, int);

D int funcPtr*(int, int);

Correct Answer: A. int (*funcPtr)(int, int);

EXPLANATION

The correct syntax for function pointer is return_type (*pointer_name)(parameter_types). Option A is correct.

Test

Q.339 Medium Functions

What will be the output?
void modify(int x) { x = x + 10; }
int main() { int a = 5; modify(a); printf("%d", a); }

A 5

B 15

C 10

D Error

Correct Answer: A. 5

EXPLANATION

Since parameters are passed by value, changes to 'x' inside modify() don't affect 'a' in main(). Output is 5.

Test

Q.340 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.

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