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Grading system
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// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file | |
// for details. All rights reserved. Use of this source code is governed by a | |
// BSD-style license that can be found in the LICENSE file. | |
import 'package:flutter/material.dart'; | |
import 'package:flutter/services.dart'; | |
void main() => runApp(MyApp()); | |
class MyApp extends StatelessWidget { | |
@override | |
Widget build(BuildContext context) { | |
return MaterialApp( | |
title: 'Flutter Demo', | |
debugShowCheckedModeBanner: false, | |
theme: ThemeData( | |
primarySwatch: Colors.blue, | |
), | |
home: const MyHomePage(title: 'Grading System'), | |
); | |
} | |
} | |
class MyHomePage extends StatefulWidget { | |
final String title; | |
const MyHomePage({ | |
Key? key, | |
required this.title, | |
}) : super(key: key); | |
@override | |
_MyHomePageState createState() => _MyHomePageState(); | |
} | |
class _MyHomePageState extends State<MyHomePage> { | |
final TextEditingController _subjectController = TextEditingController(); | |
final TextEditingController _gradeController = TextEditingController(); | |
String output = ""; | |
String error = ""; | |
Text displayOutput() { | |
if (error.isNotEmpty) { | |
return Text( | |
error, | |
style: const TextStyle(fontSize: 20.0, color: Colors.red), | |
); | |
} else { | |
return Text( | |
output, | |
style: const TextStyle(fontSize: 20.0, color: Colors.green), | |
); | |
} | |
} | |
void _calculateGrade() { | |
print('running'); | |
// Check if the user has entered a subject and grade | |
if (_subjectController.text.isEmpty || _gradeController.text.isEmpty) { | |
error = "Please enter both grade and subject"; | |
return; | |
} | |
// Check if the user has entered a valid grade | |
if (_gradeController.text.contains(".") || | |
_gradeController.text.contains("-") || | |
_gradeController.text.contains("+")) { | |
error = "Please enter a valid grade"; | |
return; | |
} | |
// Check if the user has entered a valid subject | |
final gradeValue = int.parse(_gradeController.text); | |
final subjectValue = _subjectController.text; | |
// Calculate the grade and set the output | |
if (gradeValue >= 80) { | |
output = "Your grade for $subjectValue is A"; | |
} else if (gradeValue >= 60) { | |
output = "Your grade for $subjectValue is B"; | |
} else if (gradeValue >= 50) { | |
output = "Your grade for $subjectValue is C"; | |
} else if (gradeValue >= 40) { | |
output = "Your grade for $subjectValue is D"; | |
} else { | |
output = "Your grade for $subjectValue is F"; | |
} | |
} | |
@override | |
Widget build(BuildContext context) { | |
return Scaffold( | |
appBar: AppBar( | |
title: Text(widget.title), | |
), | |
body: Center( | |
child: Column( | |
mainAxisAlignment: MainAxisAlignment.center, | |
children: [ | |
Padding( | |
padding: const EdgeInsets.all(15.0), | |
child: Row( | |
children: [ | |
Expanded( | |
child: TextField( | |
controller: _subjectController, | |
keyboardType: TextInputType.text, | |
decoration: const InputDecoration( | |
hintText: 'Enter Subject', | |
border: OutlineInputBorder(), | |
contentPadding: EdgeInsets.symmetric( | |
horizontal: 10.0, | |
vertical: 10.0, | |
), | |
), | |
onChanged: (value) { | |
// Clear the output and error | |
output = ""; | |
error = ""; | |
setState(() {}); | |
}, | |
), | |
), | |
const SizedBox(width: 10), | |
Expanded( | |
child: TextField( | |
controller: _gradeController, | |
maxLength: 3, | |
keyboardType: TextInputType.number, | |
inputFormatters: <TextInputFormatter>[ | |
FilteringTextInputFormatter.digitsOnly | |
], | |
decoration: const InputDecoration( | |
hintText: 'Enter Score', | |
border: OutlineInputBorder(), | |
counterText: "", | |
contentPadding: EdgeInsets.symmetric( | |
horizontal: 10.0, | |
vertical: 10.0, | |
), | |
), | |
onChanged: (value) { | |
// Clear the output and error | |
output = ""; | |
error = ""; | |
setState(() {}); | |
}, | |
), | |
), | |
], | |
), | |
), | |
const SizedBox(height: 20.0), | |
displayOutput(), | |
const SizedBox(height: 20.0), | |
ElevatedButton( | |
onPressed: () { | |
_calculateGrade(); | |
setState(() {}); | |
}, | |
child: const Text('Calculate'), | |
), | |
], | |
), | |
), | |
); | |
} | |
} |
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