Your First C++ Program

Your First C++ Program

The classic rite of passage in a new language is the "Hello, World!" program. Here's a complete one in C++:

#include <iostream>
using namespace std;

int main() {
    cout << "Hello world!" << endl;
    return 0;
}

Line by line

• #include <iostream> - pulls in the header that provides input and output (like cout).
• using namespace std; - lets you write cout instead of std::cout.
• int main() - the entry point. Every standalone C++ program has exactly one main(), and execution starts there.
• cout << "Hello world!" << endl; - sends the text to the console. endl moves the cursor to a new line.
• return 0; - reports that the program finished successfully.
• The curly braces { } define the "block" of code that runs.

A few quick notes

• Each statement ends with a semicolon ;.
• The double quotes around "Hello world!" are part of the command, not decorations.
• Your source file is named with a .cpp extension, like hello.cpp.

Compile and run it

Once you compile and run the program, the console should show:

Hello world!

TL;DR

• Every program has one main() where execution begins.
• #include <iostream> gives you input/output tools.
• cout << ... sends text to the console.
• return 0; means "all done, successfully".