What will be printed by: printf("%d", sizeof(float));

The correct answer is B: 4. On most systems, sizeof(float) is 4 bytes. Though technically implementation-defined, 4 bytes is standard.

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

The correct answer is A: int add(int x, int y, int z) { return x+y+z; }. func_ptr must point to a function that takes exactly 3 int parameters and returns int. Only option A matches this signature exactly.

Which of the following variable names is INVALID in C?

The correct answer is C: 123myVar. Variable names cannot start with a digit in C. Valid names must begin with a letter (a-z, A-Z) or underscore (_).

What happens when a volatile variable is declared in a multi-threaded C program?

The correct answer is B: Compiler won't optimize it away and will fetch value from memory each time. volatile tells compiler not to optimize variable accesses and to fetch fresh value from memory, useful for hardware registers and shared memory, but doesn't guarantee thread-safety without synchronization.

What does realloc() do?

The correct answer is B: Resizes an existing allocated memory block and returns new address. realloc() changes the size of previously allocated memory. It may return the same address or a new one depending on availability.

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C Programming
Data Types & Variables

C language from basics to advanced placement prep

52 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 51–52 of 52

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.51 Medium Data Types & Variables

Which of the following occupies maximum memory in a 64-bit system?

A long int

B long double

C double

D unsigned long long

Correct Answer: B. long double

EXPLANATION

In a 64-bit system, long double typically occupies 16 bytes (128 bits), which is the maximum among these options.

Test

Q.52 Medium Data Types & Variables

What will be the output of the following code?
int x = 5;
float y = x;
printf("%f", y);

A 5.000000

B Compilation error

C 5

D Garbage value

Correct Answer: A. 5.000000

EXPLANATION

Implicit type conversion occurs from int to float. The value 5 is converted to 5.0 and printed as 5.000000 with %f format specifier.

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C Programming Data Types & Variables

C Programming
Data Types & Variables