Added UI

.gitignore

@@ -1,5 +1,6 @@
 # ---> Dart
 # See https://www.dartlang.org/guides/libraries/private-files
+.idea
 
 # Files and directories created by pub
 .dart_tool/

lib/algorithms/energy.dart

@@ -1,11 +1,11 @@
 /// free fall acceleration in m/s²
-const double g = 9.81;
+const double _g = 9.81;
 
 ///
 /// Potential Energy = [mass] * [height] * g
 /// with [mass] in kg, [height] in m and result in m²kg/s² = Joule
 double potential(double mass, double height) {
-  return mass * height * g;
+  return mass * height * _g;
 }
 
 double freedPotential(double mass, double hStart, double hEnd) {

lib/main.dart

@@ -0,0 +1,43 @@
+import 'package:energy/widgets/energy_input_widget.dart';
+import 'package:energy/widgets/energy_widget.dart';
+import 'package:energy/widgets/heat_capacity_widget.dart';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+import 'models/energy_model.dart';
+
+void main() => runApp(const EnergyApp());
+
+class EnergyApp extends StatelessWidget {
+  const EnergyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return ChangeNotifierProvider(
+      create: (_) => EnergyModel(),
+      child: const MaterialApp(
+        home: EnergyHomePage(),
+      ),
+    );
+  }
+}
+
+class EnergyHomePage extends StatelessWidget {
+  const EnergyHomePage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final EnergyModel e = context.watch<EnergyModel>();
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Energy Calculation')),
+      body: Column(
+        children: [
+          EnergyInputWidget(e: e),
+          EnergyWidget(energy: e.energy),
+          HeatCapacityWidget(water: e.water, iron: e.iron),
+        ],
+      ),
+    );
+  }
+}

lib/models/energy_model.dart

@@ -0,0 +1,43 @@
+import 'package:energy/algorithms/energy.dart';
+import 'package:energy/algorithms/heat_capacity.dart';
+import 'package:flutter/material.dart';
+
+class EnergyModel with ChangeNotifier {
+  double _mass = 0.0;   // in kg
+  double _hStart = 0.0; // in m
+  double _hEnd = 0.0;
+  double _vStart = 0.0; // in m/s
+  double _vEnd = 0.0;
+
+  double get mass => _mass;
+  double get hStart => _hStart;
+  double get hEnd => _hEnd;
+  double get vStart => _vStart;
+  double get vEnd => _vEnd;
+
+  set mass(double mass) {
+    _mass = mass;
+    notifyListeners();
+  }
+  set hStart(double height) {
+    _hStart = height;
+    notifyListeners();
+  }
+  set hEnd(double height) {
+    _hEnd = height;
+    notifyListeners();
+  }
+  set vStart(double velocity) {
+    _vStart = velocity;
+    notifyListeners();
+  }
+  set vEnd(double height) {
+    _vEnd = height;
+    notifyListeners();
+  }
+
+  get energy => freedEnergy(_mass, _hStart, _hEnd, _vStart, _vEnd);
+  get water => literWaterThatCanBeBoiled(energy);
+  get iron => kgIronThatCanBeHeatetUntilRed(energy);
+
+}

lib/widgets/energy_input_widget.dart

@@ -0,0 +1,40 @@
+import 'package:energy/algorithms/velocity.dart';
+import 'package:flutter/material.dart';
+
+import '../models/energy_model.dart';
+
+class EnergyInputWidget extends StatelessWidget {
+  const EnergyInputWidget({
+    super.key,
+    required this.e,
+  });
+
+  final EnergyModel e;
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        Text("Mass ${e.mass.round()} kg"),
+        Slider(
+          value: e.mass,
+          max: 50000,
+          divisions: 1000,
+          label: "Mass",
+          onChanged: (double value) {
+            e.mass = value;
+          },
+        ),
+        Text("Initial Velocity ${e.vStart.round()} m/s"),
+        Slider(
+          value: e.vStart,
+          max: 1000,
+          divisions: 1000,
+          onChanged: (double value) {
+            e.vStart = value;
+          },
+        ),
+      ],
+    );
+  }
+}

lib/widgets/energy_widget.dart

@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart';
+
+class EnergyWidget extends StatelessWidget {
+  const EnergyWidget({
+    super.key,
+    required this.energy,
+  });
+
+  final double energy;
+
+  @override
+  Widget build(BuildContext context) {
+    return Text("Energy ${_format(energy)}Joule", style: Theme.of(context).textTheme.headlineLarge,);
+  }
+
+  String _format(double e) {
+    if (e > 1000000000000) {
+      return "${(energy / 1000000000000).round()} T";
+    } else if (e > 1000000000) {
+      return "${(energy / 1000000000).round()} G";
+    } else if (e > 1000000) {
+      return "${(energy / 1000000).round()} M";
+    } else if ( e > 1000) {
+      return "${(energy / 1000).round()} k";
+    } else {
+      return "${energy.round()} ";
+    }
+  }
+}

lib/widgets/heat_capacity_widget.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+
+class HeatCapacityWidget extends StatelessWidget {
+  const HeatCapacityWidget({
+    super.key,
+    required this.water,
+    required this.iron,
+  });
+
+  final double water;
+  final double iron;
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(children: [
+      Text("${water.round()} liter water can be boiled", style: Theme.of(context).textTheme.headlineLarge,),
+      Text("${iron.round()} kg iron can be heated", style: Theme.of(context).textTheme.headlineLarge,),]);
+  }
+}

pubspec.yaml

@@ -6,11 +6,12 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.18.0 <3.0.0"
+  sdk: ">=2.19.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
+  provider: ^6.0.0
 
 dev_dependencies:
   test:

test/algorithms/energy_test.dart

@@ -1,4 +1,4 @@
-import 'package:energy/models/energy.dart';
+import 'package:energy/algorithms/energy.dart';
 import 'package:test/test.dart';
 
 void main() {

test/algorithms/heat_capacity_test.dart

@@ -1,4 +1,4 @@
-import 'package:energy/models/heat_capacity.dart';
+import 'package:energy/algorithms/heat_capacity.dart';
 import 'package:test/test.dart';
 
 void main() {