Unity 3d Game Start and End Time

Question

I have made a timer script which starts timer when game starts. Thats fine, now what I want is when i press the "CurrentTime" button then the current time should be displayed on UI Text. For example game has started at "24:00" and after 4 minutes of play when I press the "CurrentTime" button then UI Text should display "24:04. Any help? here is my code.

public class Timer : MonoBehaviour {
    public int  Hours = 0;
    public int  Minutes = 0;
    public Text    m_text;
    private float   timestart;
    public Text ending;

    void Awake()
    {
        timestart = GetInitialTime();
    }
    void Start () {
        m_text.text = timestart.ToString();
    }

    private void Update()
    {
        if (timestart > 0f)
        {
            //  Update countdown clock
            timestart += Time.deltaTime * 0.25f;
            Hours = GetLeftHours();
            Minutes = GetLeftMinutes();

            //  Show current clock
            if (timestart > 0f)
            {
                m_text.text = Hours + ":" + Minutes.ToString("00");
            }
            else
            {
                //  The countdown clock has finished
                m_text.text = "00:00";
            }
        }
        ending.text = Hours + ":" + Minutes.ToString("00");
    }

    private float GetInitialTime()
    {
        return Hours * 60f + Minutes;
    }

    private int GetLeftHours()
    {
        return Mathf.FloorToInt(timestart / 60f);
    }

    private int GetLeftMinutes()
    {
        return Mathf.FloorToInt(timestart % 60f);
    }
}  

Answer 1

If you actually wanted the current real time it doesn't depend on the time the app was started but rather the system time itself.

Then all you need to do would be simply using System.DataTime and in particular DateTime.Now like

using System;

public class Timer : MonoBehaviour
{
    public Text m_text;

    public void GetCurrentTime()
    {
        var time = DateTime.Now;
        m_text.text = $"{time.Hour:00}:{time.Minute:00}";     
    }
}

You wouldn't need the rest of your script at all because the system itself runs the time.

---

If what you rather want is a counter I would simply do something like

public class Timer : MonoBehaviour
{
    public Text m_text;

    public float Seconds;
    public int Hours;
    public int Minutes;

    private void Start()
    {
        // in case you want to start the timer automatically
        StartTimer();
    }       

    public void StartTimer()
    {
        StopAllCoroutines();
        StartCoroutine(TimerRoutine());
    }

    public void StopTimer()
    {
        StopAllCoroutines();
        GetCurrentTime();
    }

    private IEnumerator TimerRoutine()
    {
        Seconds = 0;
        Hours = 0;
        Minutes = 0;
        while(true)
        {
            Seconds += Time.deltaTime;
            if(Seconds >= 60)
            {
                Seconds -= 60.0f;
                Minutes += 1;
                if(Minutes >= 60)
                {
                    Minutes -= 60;
                    Hours += 1;
                }
            }

            GetCurrentTime();
            yield return null;
        }
    }

    public void GetCurrentTime()
    {
        m_text.text = $"{Hours:00}:{Minutes:00}:{Seconds:00}"
    }
}