Online C++ Compiler

Welcome to the world of C++ (pronounced "C plus plus"). This is a language known for its raw power, performance, and control. If you're interested in building high-performance applications, game engines, or complex software that works close to the machine hardware, you're in the right place.

C++ can seem intimidating, but this online compiler makes it easy to start. You can compile and run your code without any complicated setup. Let's write your first program.

Write C++ Code: Type your C++ source code into the editor.

Click Run: This will compile your code into an executable program and then run it.

View the Output: The program's output will be shown in the result window.

Your First C++ Program: "Hello, World!"

This is the classic entry into C++. It introduces you to the basic structure of a program.

  #include <iostream>

int main() {
    int length = 10;
    int width = 5;
    int area = length * width;

    std::cout << "The length is: " << length << std::endl;
    std::cout << "The width is: " << width << std::endl;
    std::cout << "The area of the rectangle is: " << area;

    return 0;
}

#include <iostream>: This is a preprocessor directive. It tells the compiler to include the iostream library, which lets us work with input and output (like printing text to the screen).

int main(): This is the main function. Every C++ program starts execution here. It's the entry point.

std::cout << "...": This is how we print text. cout stands for "character output." The << operator sends the string on the right to the cout stream on the left.

return 0;: This tells the operating system that the program ran successfully. A non-zero number usually indicates an error.

Let's Try Something More: Calculating an Area

Let's use variables to calculate the area of a rectangle.

  #include <iostream>

int main() {
    std::cout << "Hello, C++ World from docodehere.com!";
    return 0;
}

Here we declare integer variables (int) for length, width, and area, perform a calculation, and then print the results in a user-friendly way. std::endl adds a new line.

C++ was built upon C. It includes almost all of C's features but adds more, most notably Object-Oriented Programming (OOP) with concepts like classes and objects.

C++ is very strict. A common error is forgetting a semicolon ; at the end of a line, or misspelling a variable name. Read the error message carefully; it often tells you exactly which line has the problem.

It means we are using a feature (cout or endl) from the standard (std) namespace. It helps avoid naming conflicts in large projects.

The power of C++ is now at your fingertips. Happy compiling!