I’m trying to make it so you can only shoot when touching the left side of the screen. This will be on mobile. I figured I would just add another if parameter, but I have an error I don't know how to fix.

using UnityEngine;
using System.Collections;

public class Flaregun : MonoBehaviour {

public Rigidbody flareBullet;
public Transform barrelEnd;
public GameObject muzzleParticles;
public AudioClip flareShotSound;
public AudioClip noAmmoSound;	
public AudioClip reloadSound;	
public int bulletSpeed = 2000;
public int maxSpareRounds = 5;
public int spareRounds = 3;
public int currentRound = 0;

private float halfScreenWidth;

private void Start()
{
	halfScreenWidth = Screen.width / 2;
}

// Update is called once per frame
void Update () 
{
	
	if(Input.GetButtonDown("Fire1") && !GetComponent<Animation>().isPlaying && Input.GetButtonDown("Fire1").position.x < halfScreenWidth)
	{
		if(currentRound > 0){
			Shoot();
		}else{
			GetComponent<Animation>().Play("noAmmo");
			GetComponent<AudioSource>().PlayOneShot(noAmmoSound);
		}
	}
	/*if(Input.GetKeyDown(KeyCode.R) && !GetComponent<Animation>().isPlaying)
	{
		Reload();
		
	}*/

}

void Shoot()
{
		currentRound--;
	if(currentRound <= 0){
		currentRound = 0;
	}
	
		GetComponent<Animation>().CrossFade("Shoot");
		GetComponent<AudioSource>().PlayOneShot(flareShotSound);
	
		
		Rigidbody bulletInstance;			
		bulletInstance = Instantiate(flareBullet,barrelEnd.position,barrelEnd.rotation) as Rigidbody; //INSTANTIATING THE FLARE PROJECTILE
		
		
		bulletInstance.AddForce(barrelEnd.forward * bulletSpeed); //ADDING FORWARD FORCE TO THE FLARE PROJECTILE
		
		Instantiate(muzzleParticles, barrelEnd.position,barrelEnd.rotation);	//INSTANTIATING THE GUN'S MUZZLE SPARKS	
}

void Reload()
{
	if(spareRounds >= 1 && currentRound == 0){
		GetComponent<AudioSource>().PlayOneShot(reloadSound);			
		spareRounds--;
		currentRound++;
		GetComponent<Animation>().CrossFade("Reload");
	}
	
}

}

What is the error?