made buttons square and added hotkeys

SharpCalculator.Avalonia/MainWindow.axaml.cs

@@ -1,3 +1,4 @@
+using Avalonia.Input;
 using FusionCalculator;
 
 namespace SharpCalculator.Avalonia;
@@ -9,6 +10,31 @@ public partial class MainWindow : Window
     public MainWindow()
     {
         InitializeComponent();
+        // https://github.com/AvaloniaUI/Avalonia/discussions/12179
+        KeyDownEvent.AddClassHandler<TopLevel>(GlobalOnKeyDown, handledEventsToo: true);
+    }
+
+    private void GlobalOnKeyDown(object? sender, KeyEventArgs e)
+    {
+        switch (e.Key)
+        {
+            case Key.Enter:
+                CalculateResult();
+                break;
+            case Key.Delete:
+                Clear();
+                break;
+        }
+    }
+
+    private void CalculateResult()
+    {
+        if(Input.Text == null || Output.Text == null || Output.Text.StartsWith("Error"))
+            return;
+        string expression = Input.Text;
+        string result = Output.Text;
+        AppendToHistory($"{expression}={result}");
+        Input.Text = result;
     }
     
     private void AppendToHistory(string line) //function of appending expression to the history list
@@ -24,6 +50,23 @@ public partial class MainWindow : Window
             .Replace("  ", " ");
     }
 
+    private void Clear()
+    {
+        Input.Clear();
+        Output.Clear();
+    }
+    
+    private void ResultButton_OnClick(object? sender, RoutedEventArgs e)
+    {
+        CalculateResult();
+    }
+    
+    
+    private void ClearButton_OnClick(object? sender, RoutedEventArgs e)
+    {
+        Clear();
+    }
+
     private void MathButton_OnClick(object? sender, RoutedEventArgs e)
     {
         if (sender is not Button button)
@@ -48,30 +91,6 @@ public partial class MainWindow : Window
             _ => buttonText
         };
     }
-    
-    private void ClearButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        Input.Text = "";
-        Output.Text = "";
-    }
-
-    private void UndoButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        // delete last digit
-        // if (!string.IsNullOrEmpty(Input.Text)) 
-        //     Input.Text = Input.Text.Remove(Input.Text.Length - 1);
-        Input.Undo();
-    }
-    
-    private void ResultButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        if(Input.Text == null || Output.Text == null || Output.Text.StartsWith("Error"))
-            return;
-        string expression = Input.Text;
-        string result = Output.Text;
-        AppendToHistory($"{expression}={result}");
-        Input.Text = result;
-    }
 
     private void Input_OnTextChanged(object? sender, TextChangedEventArgs e)
     {