How do i create lines in scene view??

Hello i am having some trouble with Lists in unity what i am trying to do is create multiple lines in the scene view but i am getting some errors, does anyone know what i am doing wrong?

Here is my code so you know what i have done.

using UnityEngine;
using System.Collections.Generic;

[ExecuteInEditMode]
public class ClickLines : MonoBehaviour {

    bool c;
    List<Vector3> s = new List<Vector3>();
    List<Vector3> e = new List<Vector3>();

    void Update()
    {
        GetInput();
    }
    void GetInput()
    {
        if (Input.GetMouseButtonDown(0))
        {
            Start();
        }
        else if (Input.GetMouseButtonUp(0))
        {
            End();
        }
    }

    void Start()
    {
        c = true;
        s = GetPoint();
        s.Add(GetPoint);

    }
    void End()
    {
        c = false;
        e = GetPoint();
    }
    Vector3 GetPoint()
    {
            RaycastHit hit;
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, out hit))
            {
                return hit.point;
            }
            return Vector3.zero;
    }
    void OnDrawGizmos()
    {
        Gizmos.DrawLine(s, e);
        Gizmos.DrawSphere(s, 0.4f);
        Gizmos.color = Color.blue;
        Gizmos.DrawSphere(e, 0.4f);
    }
}

See the modified script. Note that creating a class containing the start and end of a line is an easier way to reference a “line”. This will not work in the editor, you must press play. I am not familiar with creating editor scripts, hopefully this gives you a good idea how to achieve what youre after. Youll have to reference the editor camera rather than the main camera. There are questions already asked that cover that

using UnityEngine;
using System.Collections.Generic;

public class Line
{
    public Vector3 start;
    public Vector3 end;
    public Line(Vector3 s, Vector3 e)
    {
        start = s;
        end = e;
    }
}


//[ExecuteInEditMode]
public class ClickLines : MonoBehaviour
{

    bool c;
    private Vector3 s;
    private Vector3 e;
    public List<Line> lines = new List<Line>();
    //List<Vector3> s = new List<Vector3>();
    //List<Vector3> e = new List<Vector3>();

    void Update()
    {
        GetInput();
    }
    void GetInput()
    {
        if (Input.GetMouseButtonDown(0))
        {
            Start();
        }
        else if (Input.GetMouseButtonUp(0))
        {
            End();
        }
    }

    void Start()
    {
        c = true;
        s = GetPoint();


    }
    void End()
    {
        c = false;
        e = GetPoint();

        lines.Add(CreateLine());
    }


    Line CreateLine()
    {
        Line l = new Line(s, e);
        return l;
    }



    Vector3 GetPoint()
    {
        RaycastHit hit;
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray, out hit))
        {
            return hit.point;
        }
        return Vector3.zero;
    }
    void OnDrawGizmos()
    {
        if (lines.Count > 0)
        {
            foreach (Line l in lines)
            {
                Gizmos.color = Color.red;
                Gizmos.DrawLine(l.start, l.end);
                Gizmos.color = Color.blue;
                Gizmos.DrawSphere(l.start, 0.4f);
                Gizmos.DrawSphere(l.end, 0.4f);
            }
        }      
    }
}