Problem Set 2 Q1: Circle Calculator in Flask app

circle.py

@@ -0,0 +1,31 @@
+# Data Structures & Algorithms Spring 2024
+# Problem Set 2
+# Lonny Chen, 216697
+# circle.py
+
+import math
+
+class Circle:
+    rounding_int_default = 2
+
+    def __init__(self, radius):
+        '''Constructs Circle with instance attributes.'''
+        self.radius = radius
+
+    def area(self, rounding_int=rounding_int_default):
+        '''Returns area of this Circle with input rounding.'''
+        result = math.pi * (self.radius ** 2)
+        if rounding_int == 0:
+            rounded_result = round(result)
+        else:
+            rounded_result = round(result, rounding_int)
+        return rounded_result
+
+    def perimeter(self, rounding_int=rounding_int_default):
+        '''Returns perimeter of this Circle with input rounding.'''
+        result = 2 * math.pi * self.radius
+        if rounding_int == 0:
+            rounded_result = round(result)
+        else:
+            rounded_result = round(result, rounding_int)
+        return rounded_result

flask_app.py

@@ -1,23 +1,32 @@
-from flask import Flask, render_template, request
+# Data Structures & Algorithms Spring 2024
+# Problem Set 2
+# Lonny Chen, 216697
+# flask_app.py
 
+from flask import Flask, render_template, request
 from helper import perform_calculation, convert_to_float
+from circle import Circle
 
 app = Flask(__name__)  # create the instance of the flask class
 
-
+# route() decorator tells Flask: base URL triggers index "home page"
 @app.route('/')
 @app.route('/home')
 def home():
+    '''Home page template'''
     return render_template('home.html')
 
-
+# route() decorator tells Flask: '/calculate' URL triggers calculation
 @app.route('/calculate', methods=['GET', 'POST'])  # associating the GET and POST method with this route
 def calculate():
+    '''Calculation of mathematical operation from HTML form values, includes input error checking.'''
+
     if request.method == 'POST':
         # using the request method from flask to request the values that were sent to the server through the POST method
         value1 = request.form['value1']
         value2 = request.form['value2']
         operation = str(request.form['operation'])
+        rounding = request.form['rounding']
 
         # make sure the input is one of the allowed inputs (not absolutely necessary in the drop-down case)
         if operation not in ['add', 'subtract', 'divide', 'multiply']:
@@ -27,14 +36,62 @@ def calculate():
         try:
             value1 = convert_to_float(value=value1)
             value2 = convert_to_float(value=value2)
+            rounding_int = int(float(rounding))
+            assert rounding_int >= 0
         except ValueError:
-            return render_template('calculator.html', printed_result="Cannot perform operation with this input")
+            return render_template('calculator.html', printed_result="Entered values should be numbers!")
+        except AssertionError:
+            return render_template('calculator.html', printed_result="Rounding should not be negative!")
 
         try:
-            result = perform_calculation(value1=value1, value2=value2, operation=operation)
-            return render_template('calculator.html', printed_result=str(result))
+            result = perform_calculation(value1=value1, value2=value2, operation=operation, rounding_int=rounding_int)
+            printed_result = f'The result of {value1} {operation} {value2} is: {result} (rounded to {rounding_int} decimals)'
+            return render_template('calculator.html', printed_result=printed_result)
 
         except ZeroDivisionError:
             return render_template('calculator.html', printed_result="You cannot divide by zero")
 
     return render_template('calculator.html')
+
+# route() decorator tells Flask: '/circle' URL triggers circle calculation
+@app.route('/circle', methods=['GET', 'POST'])  # associating the GET and POST method with this route
+def circle():
+    '''Calculation of circle calculation from HTML form values, includes input error checking.'''
+
+    if request.method == 'POST':
+        # using the request method from flask to request the values that were sent to the server through the POST method
+        radius = request.form['radius']
+        operation = str(request.form['operation'])
+        rounding = request.form['rounding']
+
+        # make sure the input is one of the allowed inputs (not absolutely necessary in the drop-down case)
+        if operation not in ['perimeter', 'area']:
+            return render_template('circle.html',
+                                   printed_result='Operation must be one of "perimeter" or "area".')
+
+        try:
+            radius = convert_to_float(value=radius)
+            rounding = convert_to_float(value=rounding)
+            assert radius >= 0 and rounding >= 0
+        except ValueError:
+            return render_template('circle.html', printed_result="Entered values should be numbers!")
+        except AssertionError:
+            return render_template('circle.html', printed_result="Radius or rounding should not be negative!")
+
+        # Circle class calculations
+        rounding_int = int(rounding)
+        circle = Circle(float(radius))
+        if operation == 'perimeter':
+            result = circle.perimeter(rounding_int)
+        else:
+            result = circle.area(rounding_int)
+        printed_result = f'For a circle with radius of {radius}, the {operation} is: {result} (rounded to {rounding_int} decimals)'
+
+        return render_template('circle.html', printed_result=printed_result)
+
+    return render_template('circle.html')
+
+# So web app can be refreshed in browser after changes
+# Can just enter on command line: "python flask_app.py"
+if __name__ == '__main__':
+    app.run(debug=True)

helper.py

@@ -1,17 +1,22 @@
-# create helper functions for calculations
+# Data Structures & Algorithms Spring 2024
+# Problem Set 2
+# Lonny Chen, 216697
+# helper.py
 
+# create helper functions for calculations
 
-def perform_calculation(value1: float, value2: float, operation: str) -> float:
+def perform_calculation(value1: float, value2: float, operation: str, rounding_int: int) -> float:
     """
     Perform a mathematical operation on two values.
 
     Parameters:
         value1 (float): The first value.
         value2 (float): The second value.
         operation (str): The operation to perform. Can be 'add', 'subtract', 'divide', or 'multiply'.
+        rounding_int (int): Number of decimal places to round result to.
 
     Returns:
-        float: The result of the operation.
+        float or int: The result of the operation.
 
     Raises:
         ZeroDivisionError: If attempting to divide by zero.
@@ -25,7 +30,12 @@ def perform_calculation(value1: float, value2: float, operation: str) -> float:
     else:
         result = value1 * value2
 
-    return result
+    if rounding_int == 0:
+        rounded_result = round(result)
+    else:
+        rounded_result = round(result, rounding_int)
+
+    return rounded_result
 
 
 def convert_to_float(value: str) -> float:

templates/calculator.html

@@ -1,6 +1,6 @@
 {% extends 'layout.html' %}
 {% block content %}
-	<h1>Calculator</h1>
+	<h1>General Calculator</h1>
     <form method="post">
         <input type="text" name="value1" placeholder="Enter the first number" required="required" />
         <input type="text" name="value2" placeholder="Enter the second number" required="required" />
@@ -9,10 +9,13 @@ <h1>Calculator</h1>
         <select id="operation" name="operation">
             <option value="add">Add</option>
             <option value="subtract">Subtract</option>
-            <option value="divide">Divide</option>
             <option value="multiply">Multiply</option>
+            <option value="divide">Divide</option>
         </select>
 
+        <label for="rounding">Round to decimals</label>
+        <input type="text" name="rounding" value="2" required="required" />
+
         <button type="submit">Calculate</button>
     </form>
 

templates/circle.html

@@ -0,0 +1,23 @@
+{% extends 'layout.html' %}
+{% block content %}
+	<h1>Circle Calculator</h1>
+    <form method="post">
+        <input type="text" name="radius" placeholder="Enter the circle's radius" required="required" />
+
+        <label for="operation">Operation</label>
+        <select id="operation" name="operation">
+            <option value="perimeter">Perimeter</option>
+            <option value="area">Area</option>
+        </select>
+
+        <label for="rounding">Round to decimals</label>
+        <input type="text" name="rounding" value="2" required="required" />
+
+        <button type="submit">Calculate</button>
+    </form>
+
+   <br>
+
+   {{ printed_result }}
+
+{% endblock %}

templates/layout.html

@@ -12,6 +12,7 @@ <h1 class="logo"><a href="{{ url_for('home') }}">Home</a></h1>
         <strong><nav>
           <ul class="menu">
             <li><a href="{{ url_for('calculate') }}">General Calculator</a></li>
+              <li><a href="{{ url_for('circle') }}">Circle Calculator</a></li>
           </ul>
         </nav></strong>
       </div>

test_circle.py

@@ -0,0 +1,67 @@
+# Data Structures & Algorithms Spring 2024
+# Problem Set 2
+# Lonny Chen, 216697
+# test_circle.py
+#   Usage: pytest test_circle.py or Run in PyCharm IDE
+
+from circle import Circle
+import math
+import random
+
+def check_circle_area(radius, rounding):
+    '''A Circle with input radius returns the expected area with input rounding.'''
+    circle = Circle(radius)
+    expected = round(math.pi * (radius ** 2), rounding)
+    result = circle.area(rounding)
+    print(f'Testing area of circle with radius {radius}, rounding {rounding}')
+    print(f'Expected: {expected}')
+    print(f'Result:   {result}')
+    assert expected == result
+
+def check_circle_perimeter(radius, rounding):
+    '''A Circle with input radius returns the expected perimeter with input rounding.'''
+    circle = Circle(radius)
+    expected = round(2 * math.pi * radius, rounding)
+    result = circle.perimeter(rounding)
+    print(f'Testing perimeter of circle with radius {radius}, rounding {rounding}')
+    print(f'Expected: {expected}')
+    print(f'Result:   {result}')
+    assert expected == result
+
+def generate_random_seed(min, max):
+    '''Generate a random seed between input min and max.'''
+    seed = random.randint(min, max)
+    print(f'\nRandom seed is: {seed}') #note for reproducability
+    random.seed(seed)
+
+def test_directed_circle_area(radius_list = [0, 1, 2, math.pi, 10, 100, 1e6]):
+    '''Test Circle::area() with interesting radius values.'''
+    generate_random_seed(1, 100)
+    for r in radius_list:
+        rounding = random.randint(0, 10)
+        check_circle_area(r, rounding)
+
+def test_directed_circle_perimeter(radius_list = [0, 1, 2, math.pi, 10, 100, 1e6]):
+    '''Test Circle::perimeter() with interesting radius values.'''
+    generate_random_seed(1, 100)
+    for r in radius_list:
+        rounding = random.randint(0, 10)
+        check_circle_perimeter(r, rounding)
+
+def test_random_circle_area(iterations=10):
+    ''' Test Circle::area() with random radius and rounding for input number of iterations.'''
+    generate_random_seed(1, 100)
+    for i in range(0, iterations):
+        print(f'\nIteration #{i}')
+        radius = random.uniform(0,1000)
+        rounding = random.randint(0, 10)
+        check_circle_area(radius, rounding)
+
+def test_random_circle_perimeter(iterations=10):
+    ''' Test Circle::perimeter() with random radius and rounding for input number of iterations.'''
+    generate_random_seed(1, 100)
+    for i in range(0, iterations):
+        print(f'\nIteration #{i}')
+        radius = random.uniform(0,1000)
+        rounding = random.randint(0, 10)
+        check_circle_perimeter(radius, rounding)