How to Use the C++ Compiler

To use the C++ Compiler, follow these steps:

  1. In the code editor, write your C++ code.
  2. Click the "RUN" button to compile and run your code.
  3. The output will be displayed in the console below the code editor.

Taking Inputs

In C++, you can take inputs from the user in various ways. Here are some examples:

String Input

#include <iostream>
#include <string>

int main() {
    std::string input;
    std::cout << "Enter a string: ";
    std::getline(std::cin, input);
    std::cout << "You entered: " << input;
    return 0;

Number Input

#include <iostream>

int main() {
    int num;
    std::cout << "Enter a number: ";
    std::cin >> num;
    std::cout << "You entered: " << num;
    return 0;

Importing Libraries

C++ has a rich set of built-in libraries that can be used in your programs. Here are some examples:

Using the Math Library

#include <iostream>
#include <cmath>

int main() {
    double result = sqrt(25);
    std::cout << "Square root of 25 is " << result;
    return 0;

Using the Vector Class

#include <iostream>
#include <vector>

int main() {
    std::vector<int> arr = {1, 2, 3, 4, 5};
    for(int i : arr) {
        std::cout << i << " ";
    return 0;

Syntax 101

C++ is a general-purpose programming language that has imperative, object-oriented and generic programming features. Here's a primer on the major syntax basics of C++:


Variables in C++ must be declared with the type of data that they will store.

std::string name = "John Doe"; // Variable assignment
int age = 25; // Variable assignment

Control Structures

C++ includes control structures such as if, else, for, while, and switch.

// If-Else
if (age > 18) {
    std::cout << "Adult";
} else {
    std::cout << "Minor";

// For loop
for (int i = 0; i < 5; i++) {
    std::cout << i;


Functions in C++ are defined with the type of value they will return.

void greet(std::string name) {
    std::cout << "Hello, " << name;

greet("John Doe"); // Calls the function with "John Doe" as the argument

C++ Online Test

A C++ online test is an effective way to assess an individual's C++ programming skills, especially in the context of systems programming and game development. These tests typically include a mix of theoretical questions and practical coding challenges. By attempting these tests, candidates can demonstrate their understanding of C++ concepts, their problem-solving abilities, and their proficiency in writing efficient code. C++ online tests are commonly used in technical interviews, coding bootcamps, and online learning platforms to gauge a learner's understanding and proficiency in C++.