C++ Quiz | Practice Test / Quiz / MCQs

1. What would be the output of this code?
cpp
int i0=4, i1=6, i2=8;
int& nums[3]={i2,i0,i1};
std::cout<

There is no output. The code causes a compiler error because 'nums' is an array of references, which is illegal.468846The output is the addresses of 'i2', 'i0', and 'i1', in that order, with no spaces.

2. What is an appropriate way of removing 'my_object' as shown below?
cpp
my_class *my_object = new my_class();

Exiting the scope will destroy the object.The garbage collector will destroy the object eventually.free(my_object);''delete(my_object);

4. Which of the following is _not_ a consequence of declaring the member variable count of my_class as static?
cpp
class my_class {
public: static int count;
}

The variable is allocated only once, regardless of how many objects are instantiated because it is bound to the class itself, not its instances.The variable exists even when no objects of the class have been defined so it can be modified at any point in the source code.The variable cannot be modified by any part of the code in the same application or thread. However, other threads may modify it.All objects that try to access their count member variable actually refer to the only class-bound static count variable.

5. What is the purpose of a destructor?

It allows the programmer to write the necessary code to free the resources acquired by the object prior to deleting the object itself.It deletes an object. One example of a destructor is the 'delete()' function.There are no destructors in C++.It terminates a program. This may be achieved as a regular function call or as an exception.

6. Which statement is true when declaring the member variable 'count' as static?
cpp
class my_class{
public: static int count;
};

The variable cannot be modified by any part of the code in the same application or thread. However, other threads may modify it.The variable is allocated only once, regardless of how many objects are instantiated, because it is bound to the class itself, not its instances.All objects that try to access their count member variable actually refer to the only class-bound static count variable.The variable existd when no objects of the class have been defined, so it can be modified at any point in the source code.

7. Which of the following STL classes is the best fit for implementing a phonebook? Suppose each entry contains a name and a phone number, with no duplicates, and you want to have lookup by name.

std::map'std::liststd::vector'std::priority_queue

8. What is the output of this code?
cpp
int c=3; char d='A';
std::printf('c is %d and d is %c',c,d);

c is c and d is dc is A and d is 3c is d and d is cc is 3 and d is A

9. Which STL class is the best fit for implementing a collection of data that is always ordered so that the pop operation always gets the greatest of the elements? Suppose you are interested only in push and pop operations.

std::priority_queuestd::map''std::liststd::vector

10. What does this part of a main.cpp file do?
cpp
#include 'library.h'

It cherry picks library.h for the declarations and definitions of all data and functions used in the remainder of the source file main.cpp, finally replacing the '#include' directive by those declarations and definitions.It causes the toolchain to compile all the contents of library.h so that its executable code is available when needed by the final application.It causes the replacement of the '#include' directive by the entire contents of the source file library.h. This is similar to a Copy-Paste operation of library.h into main.cpp.It informs the linker that some functions or data used in the source file main.cpp are contained in library.h, so that they can be called in run time. This is also known as dynamic linking.

11. What's wrong with this definition when using a pre-C++11 compiler?
cpp
std::vector> thematrix;

There's nothing wrong with it.The correct syntax should be: 'std::vector[std::vector[int]] thematrix;>>' is parsed as the shift-right operator, and thus results in a compile error.An 'std::vector' cannot contain more 'std::vector' containers as its elements.

12. Which of the following shows the contents of vector v1 and v2 after running this code?
cpp
std::vector v1{1,2,3},v2;
v2=v1;
v1.push_back(4);
v2.push_back(5);

v1:{1,2,3,4}; v2:{1,2,3,5};v1:{1,2,3,4}; v2:{5};Errorv1:{1,2,3,4,5}; v2:{1,2,3,4,5};

13. What results from executing this code snippet?
cpp
int x=5, y=2;
if(x & y) {
/*_part A_*/
}
else {
/*_part B_*/
}

Part B executes because (x & y) results in 0, or false.Part A executes because x==5 (true) and y==2 (true), thus the AND operation evaluates as true.Part A executes because (x & y) results in a nonzero value, or true.Part B executes because the statement (x & y) is invalid, thus false.

14. Which statement is true?

Only classes can have member variables and methods.C++ supports multiple inheritance.C++ supports only single inheritance.Only structs can inherit.

15. Which choice is the most reasonable implementation of the function std::mutex::lock() by using std::mutex::try_lock()?

Bcppvoid std::mutex::lock(){ return (this->try_lock());}Acppvoid std::mutex::lock(){ while(!this->try_lock());}Dcppvoid std::mutex::lock(){ while(this->try_lock());}Ccppvoid std::mutex::lock(){ while(1) this->try_lock();}

16. What is the meaning of the three sections specified between parentheses in a for loop separated by semicolons?

The first is the iterating variable name, the second is the number of times to iterate, and the third is the desired increment or decrement (specified with a signed integer).The first is the iterating variable, the second is the container in which it should operate, and the third is an exit condition to abort at any time.The first is the initialization block, the second is the condition to iterate, and the third is the increment block.The first is the iterating variable name, the second is the starting value for the iterating variable, and the third is the stop value (the last value plus one).

17. What is true about the variable named 'ptr'?
cpp
void *ptr;

It is a pointer to a void function.It is a pointer initialized at NULL.It is a pointer to a value with no specific type, so it may be cast to point to any type.That declaration causes a compiler error, as pointers must specify a type.

18. What's a benefit of declaring the parameter as a const reference instead of declaring it as a regular object?
cpp
int median(const my_array& a);

The argument is passed as a reference, so the function receives a copy that can be modified without affecting the original value.Actually objects can't be passed as regular variables because they require a constructor call. Therefore a const reference is the only way to pass class instances to functions.The argument is passed as a reference, so if the passed my_array object is large, the program will require less time and memory.There are no benefits because a reference and an object are treated as the same thing.

20. What is a valid definition for the 'get_length' function, which returns the length of a null-terminated string?

Acppint get_length(char *str) { int count=0; while(str[count++]); return count-1;}Dcppint get_length(char *str) { int count=0; while(str++) count++; return count;}Bcppint get_length(char *str) { int count=0; while(str!=NULL){ count++; str++; } return count;}Ccppint get_length(char *str) { int count=0; while((*str)++) count++; return count;}

21. When placed in a valid execution context, which statement will dynamically allocate memory from the heap for an integer of value 11?

int* anInt = new int(11);'int* anInt = new int[11];'int anInt = new int(11);int anInt = new int[11];

22. Consider a class named 'complexNumber'. Which code will result in an equivalent object?
cpp
complexNumber(float real, float im)
: real_part(real),
im_part(im){}

DcppcomplexNumber(float real, float im) { this->real_part = ℜ this->im_part = &im;}BcppcomplexNumber(float real, float im) { this->real_part(real); this->im_part(im);}AcppcomplexNumber(float real, float im) { this->real = real_part; this->im = im_part;}CcppcomplexNumber(float real, float im) { this->real_part = real; this->im_part = im;}

23. Which choice is the correct declaration for the class named Dog, derived from the Animal class?
cpp
class Animal{
//....
}

Acppclass Dog :: public Animal { //....};Bcppclass Dog : public Animal { //....};Dcpppublic class Dog extends Animal { //....};Ccpppublic class Animal :: Dog { //....};

25 Questions

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25 Questions

❤ If you liked Fatskills, consider supporting us by checking out The Life Manuals You Never Got.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know? Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson© 2026 Fatskills.com

All trademarks, logos and brand names are the property of their respective owners. All company, product and service names used in this website are for identification purposes only. Use of these names, trademarks and brands does not imply endorsement.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know?
Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson
© 2026 Fatskills.com