IndexOutOfRangeException: Index was outside the bounds of the array. SwipeController.Update () (at Assets/Scripts/SwipeController.cs:38)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SwipeController : MonoBehaviour
{
    public static bool tap, swipeLeft, swipeRight, swipeUp, swipeDown;
    private bool isDraging = false;
    private Vector2 startTouch, swipeDelta;

    private void Update()
    {
        tap = swipeDown = swipeUp = swipeLeft = swipeRight = false;
        #region PC version
        if (Input.GetMouseButtonDown(0))
        {
           tap = true;
            isDraging = true;
           startTouch = Input.mousePosition;
        }
        else if (Input.GetMouseButtonUp(0))
        {
            isDraging = false;
            Reset();
        }
        #endregion

        #region Mobile version
        if (Input.touches.Length > 0)
        {
            if (Input.touches[0].phase == TouchPhase.Began)
            {
                tap = true;
                isDraging = true;
                startTouch = Input.touches[0].position;
            }
        }
        else if (Input.touches[0].phase == TouchPhase.Ended || Input.touches[0].phase == TouchPhase.Canceled)
        {
            isDraging = false;
            Reset();
        }
        #endregion
        swipeDelta = Vector2.zero;
        if (isDraging)
        {
             if (Input.touches.Length < 0)
                swipeDelta = Input.touches[0].position - startTouch;
            else if (Input.GetMouseButton(0))
                swipeDelta = (Vector2)Input.mousePosition - startTouch;
        }
        if (swipeDelta.magnitude > 100)
        {
            float x = swipeDelta.x;
            float y = swipeDelta.y;
            if (Mathf.Abs(x) > Mathf.Abs(y))
        {
            if (x < 0)
                swipeLeft = true;
            else
                swipeRight = true;
        }
        else
        {
            if (y < 0)
                swipeDown = true;
            else
                swipeUp = true;
        }
        Reset();
        }
    }
    private void Reset()
    {
        startTouch = swipeDelta = Vector2.zero;
        isDraging = false;
    }
}