Tabs

#include <stdio.h>

int main(void) {
  printf("Hello world!\n");
  return 0;
}

#include <iostream>

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

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Hello world!");
    }
}

print("Hello world!")

console.log("Hello world!");

package main

import "fmt"

func main() {
    fmt.Println("Hello world!")
}