MasterSwitch_02.cs

using UnityEngine;

namespace Section.Switch.Challenge02
{
    public class MasterSwitch_02 : MonoBehaviour
    {
        /// Challenge Overview:
        /// Create a program that changes the color of a GameObject based on key press
        ///     (1 : blue, 2 : red, 3 : green, 4 : black)

        public GameObject cube;

        private int _nextColor;

        // Update is called once per frame
        void Update()
        {
            if (Input.GetKeyDown(KeyCode.Alpha1))
            {
                _nextColor = 0;
            }

            if (Input.GetKeyDown(KeyCode.Alpha2))
            {
                _nextColor = 1;
            }

            if (Input.GetKeyDown(KeyCode.Alpha3))
            {
                _nextColor = 2;
            }

            if (Input.GetKeyDown(KeyCode.Alpha4))
            {
                _nextColor = 3;
            }

            switch (_nextColor)
            {
                case 0:
                    cube.GetComponent<Renderer>().material.color = Color.blue;
                    break;
                case 1:
                    cube.GetComponent<Renderer>().material.color = Color.red;
                    break;
                case 2:
                    cube.GetComponent<Renderer>().material.color = Color.green;
                    break;
                case 3:
                    cube.GetComponent<Renderer>().material.color = Color.black;
                    break;
                default:
                    Debug.Log("Invald Selection");
                    break;
            }
        }
    }
}