3. 隨機八位元2的補數之整數相加與驗證系統

補數該複習了...

namespace Q3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            Close();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            var rd = new Random();
            string s = "";
            for (int i = 0; i < 8; i++)
            {
                s += rd.Next(2);
            }
            textBox1.Text = s;

            s = "";
            for (int i = 0; i < 8; i++)
            {
                s += rd.Next(2);
            }
            textBox2.Text = s;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            button3_Click(null, null);
            int a = Convert.ToInt16(textBox1.Text.Substring(1), 2);
            if (textBox1.Text.StartsWith("1")) a -= 128;
            int b = Convert.ToInt16(textBox2.Text.Substring(1), 2);
            if (textBox2.Text.StartsWith("1")) b -= 128;
            int c = Convert.ToInt16(textBox3.Text.Substring(1), 2);
            if (textBox3.Text.StartsWith("1")) c -= 128;

            textBox8.Text = a + "";
            textBox7.Text = b + ""; ;
            textBox6.Text = c + "";
            textBox5.Text = textBox4.Text == "" ? "" :
                textBox4.Text == "overflow" ? "溢位" : "不足位";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            int a = Convert.ToInt16(textBox1.Text.Substring(1), 2);
            if (textBox1.Text.StartsWith("1")) a -= 128;
            int b = Convert.ToInt16(textBox2.Text.Substring(1), 2);
            if (textBox2.Text.StartsWith("1")) b -= 128;

            textBox4.Text = "";
            int r = a + b;
            if (r < -128)
            {
                r = 128 + (r + 128);
                textBox4.Text = "underflow";
            }
            else if (r > 127)
            {
                r = -128 + (r - 128);
                textBox4.Text = "overflow";
            }

            bool neg = r < 0;
            if (neg)
            {
                r += 128;
            }
            textBox3.Text = (neg ? 1 : 0) + Convert.ToString(r, 2).PadLeft(7, '0');
        }
    }
}