C++ Programming Practice MCQs

Question 1

Which programming styles does C++ support?

Accepted Answer

C. Procedural, object-oriented and generic programming

Answer

Object-oriented only, because every function must belong to a class

Answer

Procedural only; classes are provided by a separate library

Answer

Procedural, object-oriented and generic programming

Answer

Functional only, with all mutable state forbidden

Question 2

Which phase handles #include directives?

Accepted Answer

D. Preprocessing

Answer

Compilation (parsing and type checking)

Answer

Linking

Answer

Loading

Answer

Preprocessing

Question 3

Which build phase connects a call in main.o to the function's definition in math.o?

Accepted Answer

D. Linking

Answer

Preprocessing

Answer

Compilation

Answer

Loading

Answer

Linking

Question 4

Which statement correctly contrasts C++ with C?

Accepted Answer

B. C++ adds classes, references, overloading, templates and exceptions to C

Answer

Every valid C program is automatically a valid C++ program

Answer

C++ adds classes, references, overloading, templates and exceptions to C

Answer

C++ removed pointers and manual memory management from C

Answer

C++ is interpreted at runtime, whereas C is compiled ahead of time

Question 5

What return type does the C++ standard require for main?

Accepted Answer

B. int

Answer

void

Answer

int

Answer

bool

Answer

unsigned int

Question 6

After #include <iostream>, with no using declaration or directive, which statement compiles?

Accepted Answer

D. std::cout << "Hi";

Answer

cout << "Hi";

Answer

iostream::cout << "Hi";

Answer

std.cout << "Hi";

Answer

std::cout << "Hi";

Question 7

Which header must be included to use std::cout?

Accepted Answer

A. <iostream>

Answer

Answer

Answer

Answer

Question 8

What does a declaration such as double area(double radius); introduce?

Accepted Answer

A name with type information so calls can be checked

Answer

The compiled machine code for the function body

Answer

Storage for the function's local variables

Answer

A guarantee that a definition will be linked

Question 9

Which line is a function definition rather than only a declaration?

Accepted Answer

C. double area(double r) { return 3.14159 * r * r; }

Answer

double area(double radius);

Answer

extern double area(double);

Answer

double area(double r) { return 3.14159 * r * r; }

Answer

double area(double);

Question 10

What does this code print? int count = 1; int Count = 2; std::cout << count + Count;

Accepted Answer

B. 3

Answer

Compilation error: count is declared twice

Answer

3

Answer

2

Answer

4

Question 11

Which text begins a comment that runs to the end of the current line?

Accepted Answer

C. //

Answer

/*

Answer

#

Answer

//

Answer

--

Question 12

main.cpp includes circle.hpp, which declares double area(double), and calls area(2.0). The build command is g++ -std=c++17 main.cpp -o app, so circle.cpp (which defines area) is not compiled. What happens?

Accepted Answer

D. main.cpp compiles, but linking fails with an undefined reference to area

Answer

Preprocessing fails because circle.hpp contains no function body

Answer

Compilation of main.cpp fails because area is undeclared

Answer

The program builds and area returns 0.0 at runtime

Answer

main.cpp compiles, but linking fails with an undefined reference to area

Question 13

What does undefined behaviour mean in C++?

Accepted Answer

C. The standard places no requirements on that execution

Answer

The program must throw an exception at the faulty operation

Answer

The result is a random but otherwise harmless value

Answer

The standard places no requirements on that execution

Answer

The compiler must reject the program with an error

Question 14

What does std::endl do in addition to inserting a newline?

Accepted Answer

C. Flushes the output stream

Answer

Inserts a second blank line

Answer

Closes the output stream

Answer

Flushes the output stream

Answer

Clears the stream's error flags

Question 15

Which C++17 feature lets auto [key, value] = entry; unpack a std::pair into two named variables?

Accepted Answer

B. Structured bindings

Answer

Fold expressions

Answer

Structured bindings

Answer

Inline variables

Answer

Class template argument deduction

C++ Programming Practice MCQs

C++ Programming Free MCQs