Online Coding Lessons C and C++ Coding 2 — Questions and Answers
Question 1: In C, what does the sizeof operator return for an int on most modern 64-bit systems?
- 2 bytes
- 4 bytes (Correct answer)
- 8 bytes
- 1 byte
Correct answer: 4 bytes
An int is typically 4 bytes on most modern platforms regardless of 32- or 64-bit.
Question 2: Which C++ keyword is used to prevent a member function from modifying the object's state?
- static
- const (Correct answer)
- volatile
- mutable
Correct answer: const
Marking a member function const guarantees it will not modify the object's members.
Question 3: What is the result of the C expression 7 / 2 when both operands are integers?
- 3.5
- 3 (Correct answer)
- 4
- 3.0
Correct answer: 3
Integer division in C truncates the fractional part, yielding 3.
Question 4: In C++, which container provides automatic dynamic resizing and contiguous storage?
- std::list
- std::vector (Correct answer)
- std::map
- std::set
Correct answer: std::vector
std::vector stores elements contiguously and grows automatically as needed.
Question 5: What does the C standard library function malloc return when allocation fails?
- 0 as an int
- NULL (Correct answer)
- -1
- An uninitialized pointer
Correct answer: NULL
malloc returns NULL when it cannot allocate the requested memory.
Question 6: Which operator is used to access a struct member through a pointer in C?
- .
- -> (Correct answer)
- ::
- &
Correct answer: ->
The arrow operator -> dereferences a pointer and accesses the member in one step.
Question 7: In C++, what does the 'new' operator do that 'malloc' does not?
- Allocates on the stack
- Calls the object's constructor (Correct answer)
- Returns void*
- Never throws
Correct answer: Calls the object's constructor
new allocates memory and invokes the constructor, while malloc only allocates raw bytes.
Online Coding Lessons C and C++ Coding 2
In C, what does the sizeof operator return for an int on most modern 64-bit systems?