Hello, world!

Python

print("Hello, world!")

C#

using System;

namespace Program
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello, world!");
        }
    }
}

Java

public class Program {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

C++

#include <iostream>

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

Ruby

puts "Hello, world!"