C++ Interview Questions - C++11/14/17/20

Welcome to our comprehensive guide on C++ Interview Questions! In this lesson, we'll cover key topics and questions that every C++ developer should be familiar with. This guide is perfect for beginners and intermediates who are looking to upskill and prepare for job interviews.

Let's dive into the world of C++! 🎯

Introduction to C++

Before we start, let's quickly introduce C++ and its versions.

C++ is a powerful, high-performance, and versatile programming language that supports both procedural and object-oriented programming paradigms. C++11, C++14, C++17, and C++20 are the latest versions of C++, each introducing new features and improvements to the language.

📝 Note: Knowing the differences and features of these versions is crucial in interview scenarios.

Basic C++ Concepts

Variables and Data Types

In C++, we have several data types, including:

Integer Types (int, short, long, long long)
Floating-Point Types (float, double, long double)
Character Type (char)

Variables are used to store data. To create a variable, you first specify its data type and then give it a name.

cpp

int age = 25; // An integer variable named 'age' with the value 25
double pi = 3.14; // A floating-point variable named 'pi' with the value 3.14
char grade = 'A'; // A character variable named 'grade' with the value 'A'

Operators

C++ provides various operators to manipulate and combine values. Some common operators include:

Arithmetic Operators (+, -, *, /, %)
Assignment Operator (=)
Comparison Operators (<, >, ==, !=, <=, >=)
Logical Operators (&&, ||, !)

Control Structures

Control structures allow you to control the flow of your program. In C++, we have:

If-else Statements
Switch-Case Statements
Loops (for, while, do-while)

Functions

Functions in C++ are blocks of code that perform specific tasks. To create a function, you specify the function name, return type, and parameters.

cpp

void greet() {
  cout << "Hello, World!";
}

int main() {
  greet();
  return 0;
}

C++ Interview Questions

Question 1 💡

Which of the following are valid data types in C++?

short double
long int
char float

Correct: All of the above (short double, long int, char float) are valid data types in C++. ✅

Question 2 💡

What does the cout keyword in C++ represent?

Correct: cout is a standard output stream object provided by C++'s Standard Template Library (STL) for printing output to the console. ✅

Question 3 💡

What is the purpose of the main() function in a C++ program?

Correct: The main() function is the entry point of a C++ program. All C++ programs must have a main() function for the program to run. ✅

Conclusion

We've covered the basics of C++, including variables, data types, operators, control structures, functions, and some common interview questions. With this foundation, you're well on your way to mastering C++. Happy coding! 💡📝🎯