I'm working on a typing speed program in C# using Windows Forms, and I'm having trouble calculating the letters per minute (PPM) correctly. The program uses a Stopwatch to measure the elapsed time, and the calculation is based on the number of key presses. However, the PPM calculation is returning incorrect values.

Here is the relevant part of the code:

using System.Diagnostics; 
using System.Linq.Expressions;

namespace DAM_M07_UF1_PT1_Chamorro1_Alex
{
    public partial class Form1 : Form
    {
        private string time;
        private Stopwatch stopwatch;
        Random generator = new Random();
        int timesPressed;
        public string[] panels = {
        "There is already a vending machine for couples. It sounds like a joke, but there is already a vending machine for couples in some places. The idea is that, if we already have machines for so many things, why not a vending machine for couples? In a world where everything seems automated, now even relationships can arise from a vending machine for couples.",

        "Confusing, doubtful, dark. Sometimes, everything feels confusing, doubtful, dark. When you don't have the answers, everything feels confusing, doubtful, dark, and you don't know where to go. In moments like these, it's normal to feel confused, doubtful, dark, because the path isn't always clear. You just have to remember that, even though it feels confusing, doubtful, dark, there is always a way out.",

        "No plans, no schedules, and no phones. Sometimes you just want to live without plans, no schedules, and no phones. Escape from everything, no plans, no schedules, and no phones, to truly disconnect. It's a liberating idea: no plans, no schedules, and no phones. This way you could live each moment without worrying about the clock or the phone. No plans, no schedules, and no phones, just to be at peace.",

        "Riding a bike from Norway to Portugal. Can you imagine what it would be like to ride a bike from Norway to Portugal? It would be an incredible adventure: riding a bike from Norway to Portugal, passing through so many places. The views, the villages, the people you would meet if you decided to ride a bike from Norway to Portugal. It would be an unfettable trip, riding a bike from Norway to Portugal, with the freedom of the road.",

        "Crab, jellyfish, and starfish. In the sea, you see creatures like the crab, jellyfish, and starfish. They are fascinating: crab, jellyfish, and starfish, each with its own shape and movement. You watch how the crab, jellyfish, and starfish move in their habitat. Crab, jellyfish, and starfish, forming a small world of marine life.",

        "Pass programming. The goal is clear: pass programming. You know that if you put in the effort, you'll pass programming and feel the achievement. All those exercises and practices are leading you to one goal: pass programming. Even though it's hard, you remind yourself that the important thing is to pass programming, and that every step brings you closer to the goal.",

        "Are we the two of us or is it just a thousand things? Sometimes I wonder if it's just the two of us or if it's a thousand things. Maybe everything is confusing, and we don't know if it's just the two of us or a thousand things in our minds. If we think about it, whether it's the two of us or just a thousand things, maybe it's an enigma we'll never solve. But in the end, what matters is whether it's the two of us or just a thousand things we can't control.",

        "The early bird catches the worm. They always say: 'The early bird catches the worm.' It's a saying that repeats because the early bird catches the worm by taking advantage of the day. And even though it's sometimes hard to get up early, you remember that the early bird catches the worm. This saying inspires you, and you know that the early bird catches the worm to achieve their goals.",

        "I’m going to make him an offer he can't refuse. When you want to achieve something, you say: 'I'm going to make him an offer he can't refuse.' It's the idea of making something so good that you say: I'm going to make him an offer he can't refuse. Sometimes you have to take risks and think: I'm going to make him an offer he can't refuse. Because in the end, opportunities come when someone says: I'm going to make him an offer he can't refuse.",

        "Living alone is like being at a party where no one notices you. Sometimes, living alone feels like being at a party where no one notices you. You have freedom, but you might also feel that living alone is like being at a party where no one notices you. Independence is beautiful, even though living alone feels like being at a party where no one notices you. You find a unique peace, even though living alone feels like being at a party where no one notices you."
        };

        public Form1()
        {
            InitializeComponent();
            stopwatch = new Stopwatch();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void startButton_Click(object sender, EventArgs e)
        {
            int selection = generator.Next(0, panels.Length);
            typingTextBox.Text = panels[selection];
            stopwatch.Restart(); 
            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            TimeSpan ts = stopwatch.Elapsed;
            var hours = ts.Hours;
            var minutes = ts.Minutes;
            var seconds = ts.Seconds;
            var milliseconds = ts.Milliseconds;
            time = $"{hours}:{minutes}:{seconds}:{milliseconds}";
            clock.Text = time;
        }

        private void timerButton_Click(object sender, EventArgs e)
        {
            resumeButton.Enabled = true;
            timer1.Stop();
            stopwatch.Stop();
            userTextBox.Enabled = false;
        }

        private void resumeButton_Click(object sender, EventArgs e)
        {
            resumeButton.Enabled = false;
            stopwatch.Start(); 
            timer1.Start();
            userTextBox.Enabled = true;
        }

        private void userTextBox_TextChanged(object sender, EventArgs e)
        {
            timesPressed++;
        }

        private void checkButton_Click(object sender, EventArgs e)
        {
            int errorCount = 0;
            string text = userTextBox.Text;
            string correctText = typingTextBox.Text;

            // Compare each character
            for (int i = 0; i < text.Length; i++)
            {
                if (text[i] != correctText[i])
                {
                    errorCount++;
                }
            }

            // If no errors, calculate letters per minute
            if (errorCount == 0)
            {
                TimeSpan ts = stopwatch.Elapsed;
                double totalSeconds = ts.TotalSeconds; // Use seconds for more accurate calculation
                double lettersPerSecond = totalSeconds > 0 ? timesPressed / totalSeconds : 0;
                double lettersPerMinute = lettersPerSecond * 60; // Convert to letters per minute

                // Round the value
                lettersPerMinute = Math.Round(lettersPerMinute, 2);

                MessageBox.Show($"Letters per minute: {lettersPerMinute}");
            }
            else
            {
                MessageBox.Show($"Something is not quite right, you have {errorCount} errors.");
            }
        }
    }
}

Problem:

The calculation of PPM seems incorrect, even though the stopwatch is measuring elapsed time. The timesPressed variable increments every time the user types a character, but the letters per minute are calculated by dividing the number of key presses by the total seconds elapsed. The result doesn't seem accurate, and I’m not sure where the issue is.

What I’ve Tried:

• I've used Stopwatch.Elapsed to get the total time in seconds, then calculated letters per second and converted it to letters per minute.

• I also considered that the TextChanged event might be firing too often, but I'm still getting inaccurate results.

Questions:

1. Is the Stopwatch method I'm using the correct approach to measure elapsed time for calculating typing speed?

2. How can I improve the accuracy of the letters per minute calculation?

3. Are there any better ways to track key presses and elapsed time in a typing speed program?