ResearchOnlineJudgeEnvironment.cs

using System;
using System.Runtime.InteropServices;

class Program
{
    static void Main()
    {
        Console.WriteLine($"{nameof(RuntimeInformation.ProcessArchitecture),-20}: {RuntimeInformation.ProcessArchitecture}");
        Console.WriteLine($"{nameof(RuntimeInformation.OSArchitecture),-20}: {RuntimeInformation.OSArchitecture}");
        Console.WriteLine($"{nameof(Environment.OSVersion),-20}: {Environment.OSVersion}");
        Console.WriteLine($"{nameof(RuntimeInformation.OSDescription),-20}: {RuntimeInformation.OSDescription}");
        Console.WriteLine($"{nameof(RuntimeInformation.RuntimeIdentifier),-20}: {RuntimeInformation.RuntimeIdentifier}");
        Console.WriteLine($"{nameof(RuntimeInformation.FrameworkDescription),-20}: {RuntimeInformation.FrameworkDescription}");

        unsafe { int* p = (int*)0; } // unsafe

        var tuple = (0, 1.0);                                       // C# 7.0
        int default_expressions = default;                          // C# 7.1
        var digit_separator_after_base_specifier = 0b_0;            // C# 7.2
        Span<int> stackalloc_initializers = stackalloc int[] { 1 }; // C# 7.3
        var ranges = (new int[10])[1..4];                           // C# 8.0
        nint native_ints = 1;                                       // C# 9.0
        const string constant_interpolated_strings = $"";           // C# 10.0
        var utf8_string_literals = "0"u8;                           // C# 11.0
        int[] collection_expressions = [0];                         // C# 12.0
    }
}