// -*- java -*-

// smallest
// the smallest running program doing nothing
class smallest { static void Main() { } }

// hello world
// print a simple string on stdout
class hello_world {
   static void Main() {
      System.Console.WriteLine("Hello World");
   }
}


// argv
// access command line parameters (no segmentation fault accepted, nor silent exception, so some languages must explicitly check the presence of the argument)
class argv {
   static void Main(string[] args) {
      if (args.Length > 0) System.Console.WriteLine(args[0]);
   }
}


// env
// access environment variable
using System;

class env {
    static void Main() {
	Console.WriteLine(Environment.GetEnvironmentVariable("HOME"));
    }
}


// test file exists
// return exit code error (non zero) if a file does not exist
public class exists {
    static int Main() {
	return (new System.IO.FileInfo("/etc/mtab")).Exists ? 0 : 1;
    }
}


// test file readable
// return exit code error (non zero) if a file is not readable
public class readable {
    static int Main() {
	try {
	    (new System.IO.FileInfo("/etc/mtab")).OpenRead();
	    return 0;
	} catch(System.Exception ex) {
	    return 1;
	}
    }
}


// formatting
// print integers in a simple formatted string
class formatting {
   static void Main() {
      int a=1, b=2;
      System.Console.WriteLine("{0} + {1} = {2}", a, b, a + b);
   }
}


// system
// call an external program and check the return value
using System;
using System.Diagnostics;

public class system {
    static void Main() {
	Process proc = new Process();
	proc.EnableRaisingEvents = false;

	proc.StartInfo.FileName = "false";
	proc.Start();
	proc.WaitForExit();
	if (proc.ExitCode != 0) Console.Error.WriteLine("false failed");

	proc.StartInfo.FileName = "echo";
	proc.StartInfo.Arguments = "done";
	proc.Start();
	proc.WaitForExit();
    }
}