using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        int[] values = new int[]{3, 5, 7};

        int sum = Sum(values);

        PrintResult(sum);

        var sum2 = LinqSum(values);

        PrintResult(sum2);

    }

    static void PrintResult(int sum) {

                if (sum == 15)

            Console.WriteLine("Correct.");

        else

            Console.WriteLine("Incorrect.");

    }

​

    static int Sum(int[] values)

    {

        var sum = 0;

        foreach (var val in values) {

            sum += val;

        }

        return sum;

    }

    static int LinqSum(int[] values) {

        return values.Sum();

    }

}