Programming Finite State Machines in Unity3D using C#

using UnityEngine;
using System.Collections;
 
public class FiniteStateMachine : Monobehaviour {
 
    // Create the delegate
    private delegate void FState ();
 
    // Create a holder for the delegate
    private FState stateMethod;
 
    #region UnityEngine methods
 
    /// <summary>
    /// Sets up the controller and puts the object into the new mode.
    /// </summary>
    void Start ()
    {
        stateMethod = new FState (EnterStateA);
    }
 
    /// <summary>
    /// Executes in every frame once. Only calls the current state method.
    /// </summary>
    void FixedUpdate ()
    {
        stateMethod ();
    }
 
    #endregion
 
    #region State A
 
    /// <summary>
    /// Sets up State A.
    /// </summary>
    private void EnterStateA () {
        // Things to prepare State A come here.
 
        stateMethod = new FState (StateA);
 
        // The next line will ensure that the first run of State A
        // will occur in the same frame. Commenting this line out
        // will delay execution to the next frame.
        stateMethod();
    }
 
    /// <summary>
    /// The actual state that is being repeated every frame.
    /// </summary>
    private void StateA () {
        // Code goes here ...
 
        // Conditions to switch into another state go here
 
        if (someConditionApplies ()) {
            stateMethod = new FState (EnterStateB);
            ExitStateA ();
        }
    }
 
    /// <summary>
    /// Clean up method for state A.
    /// </summary>
    private void ExitStateA () {
        // All the stuff that needs to be cleaned up comes here.
    }
 
    #endregion
 
    #region State B
 
    /// <summary>
    /// Sets up State B.
    /// </summary>
    private void EnterStateB () {
        // Things to prepare State B come here.
 
        stateMethod = new FState (StateB);
 
        // The next line will ensure that the first run of State B
        // will occur in the same frame. Commenting this line out
        // will delay execution to the next frame.
        stateMethod();
    }
 
    /// <summary>
    /// The actual state that is being repeated every frame.
    /// </summary>
    private void StateB () {
        // Code goes here ...
 
        // Conditions to switch into another state go here
 
        if (someConditionApplies ()) {
            stateMethod = new FState (EnterStateA);
            ExitStateB ();
        }
    }
 
    /// <summary>
    /// Clean up method for state B.
    /// </summary>
    private void ExitStateB () {
        // All the stuff that needs to be cleaned up comes here.
    }
 
    #endregion
}