How to Ground check a character?

Questions & Answers
1

I am following a tutorial and I don’t know if it’s because I have the newer version or I did something incorrectly. (I realized some of the scripts were not valid in the updated Unity.)
I can constantly hit the space bar and my character will continue to jump.
I tried making an ‘Empty Child’ but it didn’t recognize that I placed with the player.
I have no clue how to fix this issue.

using UnityEngine;
using System.Collections;

public class Rose_Contoller : MonoBehaviour {
	

	public Transform groundCheck;
	public float groundCheckRadius;
	public LayerMask WhatIsGround;
	private bool grounded;
	
	public float moveSpeed;
	public float jumpHeight;
	
	// Use this for initialization
	void Start () {
	}
	void FixedUpdate () {
		grounded = Physics2D.OverlapCircle(groundCheck.position,groundCheckRadius,WhatIsGround);
	} 
	// Update is called once per frame
	void Update () {
		
		if (Input.GetKeyDown(KeyCode.Space)){
			
			GetComponent <Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x,jumpHeight);
		}
		
		if (Input.GetKey(KeyCode.D)){
			
			GetComponent <Rigidbody2D>().velocity = new Vector2(moveSpeed,GetComponent<Rigidbody2D>().velocity.y);
		}
		
		if (Input.GetKey(KeyCode.A)){
			
			GetComponent <Rigidbody2D>().velocity = new Vector2(-moveSpeed,0);
		}
	}
}
2

If you are talking about what I think you are to ground check just do an OnCollisionEnter then an if statement like this:

private void OnCollisionEnter(Collision other)
    {
        if (other.gameObject.tag == "Ground")
            isgrounded = true;
    }

Make sure you have a is grounded variable that you use.