C#

if (btn.Text == "By")

private void button1_Click(object sender, EventArgs e)
    {
    button1.Text = button1.Text == "Hello" ? "Goodbye" : "Hello";
    }

private void btn_Click(object sender, EventArgs e)
{
        if (folder.Visible==true )
        {
           btn.Text = "Hi"; 
         }         
         else
         {
            btn.Text = "By";
         }
}

btn.Text = "WTF!";

private void btn_Click(object sender, EventArgs e)
{
        if (folder.Visible==true )
        {
           btn.Text = "Hi";
         }
         else
         {
            btn.Text = "By";
         }

}

declare array of size n

for count = 0, count less than n
  create a new instance of button
  set the text of the button
  add it to the parent control collection (where parent could be a form, a panel, or the like)
end for  

public Form1()
       {
           InitializeComponent();

           var buttons = new Button[5];
           for (int i = 1; i < buttons.Length; i++)
           {
               buttons[i] = new Button();
               buttons[i].Text = "[button" + i + "]";
               buttons[i].Location = new Point(0, 25 * i);
           }

           Controls.AddRange(buttons);
       }