C#

var result = new Tuple<Double, Double, Double>(a, b, c);
return new Tuple<Double, Double>(test_val, test_2);

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestingFunctions
{
    class Program
    {
        public static Tuple<double, double> Test(double value1, double value2, double value3)
        {
            double result1 = value1 + value2 + value3;
            double result2 = 7;
            return new Tuple(result1, result2);
        }
        static void Main(string[] args)
        {
            double a = 1, b = 2, c = 3;
            Tuple result = Test(a, b, c);
            Console.WriteLine("{0}", result);
        }
    }
}

BillWoodruff wrote:

For this reason, I voted your response a #1

public class Result
{
    public double FirstNumber { get; set; }
    public double SecondNumber { get; set; }
    public double ThirdNumber { get; set; }
    // And you can create more ....
}

public static Result Do(params double[] numbers)
{
    Result result = new Result();

    result.FirstNumber = numbers[0] - numbers[1];

    foreach (double number in numbers)
        result.SecondNumber += number;
    
    return result;
}

private Tuple<CheckState, DateTime, string, decimal> _fourTuple;

private void SaveTupleButtonClick(object sender, EventArgs e)
{
    _fourTuple = Tuple.Create
    (
        checkBox1.CheckState,
        dateTimePicker1.Value,
        textBox1.Text, 
        numericUpDown1.Value
    );
}

private void SaveTupleButton_Click(object sender, EventArgs e)
{
    _fourTuple = new Tuple<CheckState, DateTime, string, decimal>
    (
        checkBox1.CheckState,
        dateTimePicker1.Value,
        textBox1.Text, 
        numericUpDown1.Value
    );
}

private void RestoreTupleClick(object sender, EventArgs e)
{
    checkBox1.CheckState = _fourTuple.Item1;
    dateTimePicker1.Value = _fourTuple.Item2;
    textBox1.Text = _fourTuple.Item3;
    numericUpDown1.Value = _fourTuple.Item4;
}

struct State
{
  public CheckState Value;
  public DateTime When;
  public string By;
  public decimal Amount;
}

Quote:

I am still eager to here how you use anonymous classes

"Anonymous classes handle most of these cases and cleaner in my opinion.
Who knows what Item0 and Item1 and Item2 is?"

public class Pair<T>
{
    private T first;
    private T second;

    public Pair(T first, T second)
    {
        this.first = first;
        this.second = second;
    }

    public T First { get { return first; } }
    public T Second { get { return second; } }
}

public static Double Test(Double Val1, Double Val2, Double Val3)
{
    Double Test_Val = Val1 + Val2 + Val3;
    Double Second_Test = Test_Val % 2;
    return new Pair<Double>(Test_Val, Second_Test);
}

public static Double Test(Double Val1, Double Val2, Double Val3, out Double secondResult)
{
    Double Test_Val = Val1 + Val2 + Val3;
    secondResult = Test_Val % 2;
    return Test_Val;
}

Use  ref and out keyword to return multiple values from function
return statement returns only single value. 

public static Double[] Test(Double Val1, Double Val2, Double Val3)
        {

            Double Test_Val = Val1 + Val2 + Val3;
            Double Second_Test = Test_Val % 2;
            double [] arr = { Test_Val, Second_Test };
            return arr;
            //return Second_Test;//I need to return this value also(two values, NOT ONE.)
        }