OddEvenSumMinMax.cs

using System;

public class OddEvenSumMinMax
{
    static void Main()
    {
        var numberCount = double.Parse(Console.ReadLine());

        var oddMax = double.MinValue;
        var oddMin = double.MaxValue;
        var oddSum = 0d;

        var evenMax = double.MinValue;
        var evenMin = double.MaxValue;
        var evenSum = 0d;

        for (var i = 0; i < numberCount; i++)
        {
            var currentNumber = double.Parse(Console.ReadLine());
            if (i % 2 == 0)
            {
                if (currentNumber > oddMax)
                {
                    oddMax = currentNumber;
                }
                if (currentNumber < oddMin)
                {
                    oddMin = currentNumber;
                }
                oddSum += currentNumber;
            }
            else
            {
                if (currentNumber > evenMax)
                {
                    evenMax = currentNumber;
                }
                if (currentNumber < evenMin)
                {
                    evenMin = currentNumber;
                }
                evenSum += currentNumber;
            }
        }

        Console.WriteLine("OddSum={1},{0}OddMin={2},{0}OddMax={3},{0}EvenSum={4},{0}EvenMin={5},{0}EvenMax={6}{0}",
            Environment.NewLine,
            oddSum,
            oddMin.Equals(double.MaxValue) ? "No" : oddMin.ToString(),
            oddMax.Equals(double.MinValue) ? "No" : oddMax.ToString(),
            evenSum,
            evenMin.Equals(double.MaxValue) ? "No" : evenMin.ToString(),
            evenMax.Equals(double.MinValue) ? "No" : evenMax.ToString());
    }
}