private void ValueButtons(char numberButton)
 {
     if (Screen.Text == "")
     {
         if (Screen.Text == "" && numberButton != '.')
         {
             Screen.Text    = $"{Screen.Text}{numberButton}";
             History.Text  += numberButton;
             CountingInput += numberButton;
         }
         else
         {
             Screen.Text    = $"0.";
             History.Text  += "0.";
             CountingInput += "0.";
         }
     }
     else
     {
         if (CountingInput.Last() == '+' || CountingInput.Last() == '-' || CountingInput.Last() == '*' || CountingInput.Last() == '/')
         {
             Screen.Text    = "";
             Screen.Text    = $"{numberButton}";
             History.Text  += numberButton;
             CountingInput += numberButton;
         }
         else
         {
             if (Screen.Text == "0" && numberButton != '.')
             {
                 Screen.Text    = $"{numberButton}";
                 History.Text   = History.Text.TrimEnd(History.Text.Last());
                 CountingInput  = CountingInput.TrimEnd(CountingInput.Last());
                 History.Text  += numberButton;
                 CountingInput += numberButton;
             }
             else
             {
                 Screen.Text    = $"{Screen.Text}{numberButton}";
                 History.Text  += numberButton;
                 CountingInput += numberButton;
             }
         }
     }
 }
 private void BackSpaceButton_Click(object sender, RoutedEventArgs e)
 {
     if (Screen.Text != "")
     {
         if (!(CountingInput.Last() == '+' || CountingInput.Last() == '-' || CountingInput.Last() == '*' || CountingInput.Last() == '/'))
         {
             CountingInput = CountingInput.Substring(0, CountingInput.Length - 1);
             History.Text  = History.Text.Substring(0, History.Text.Length - 1);
             Screen.Text   = Screen.Text.Substring(0, Screen.Text.Length - 1);
             if (Screen.Text == "-")
             {
                 Screen.Text   = "";
                 CountingInput = CountingInput.Substring(0, CountingInput.Length - 1);
                 History.Text  = History.Text.Substring(0, History.Text.Length - 1);
             }
         }
     }
 }
 private void ActionButton(string mathaction)
 {
     if (Screen.Text != "")
     {
         if (CountingInput.Last() == '+' || CountingInput.Last() == '-' || CountingInput.Last() == '*' || CountingInput.Last() == '/')
         {
             History.Text   = History.Text.TrimEnd(History.Text.Last());
             History.Text  += mathaction;
             CountingInput  = CountingInput.TrimEnd(CountingInput.Last());
             CountingInput += mathaction;
         }
         else
         {
             History.Text  += mathaction;
             CountingInput += mathaction;
         }
     }
 }