var store = new NumberStore(); Console.WriteLine($"Original sequence: {store.ToString()}"); int number = 16; ref var value = ref store.FindNumber(number); value *= 2; Console.WriteLine($"New sequence: {store.ToString()}"); // The example displays the following output: // Original sequence: 1 3 7 15 31 63 127 255 511 1023 // New sequence: 1 3 7 15 62 63 127 255 511 1023