using System; namespace Test { class Program { static void Main() { int[] a = { 5, 8, -3, 6, -4, 12, -19, 7, -2, 11 }; int sum = 0; for(int i = 1; i < a.Length; i++) { if(i % 2 != 0) { sum += a[i]; } } Console.WriteLine("Sum: " + sum); Console.ReadKey(); } } }