Initial commit with refactor

refactored_polygon.py

@@ -0,0 +1,103 @@
+import turtle
+# Always put imports at the top
+
+# We put the core logic into a function, so that in the future if we want to use one of the other functions
+# (eg the get_number function), we can simply import it from this file and use it.
+# If we left everything outside a function, the code would be run when trying to import one of the other functions
+def run():
+    print('**************************************')
+    print('Welcome to DumbCAD 1.01')
+
+    # \n adds a new line (there is one put in automatically at the end of a print statement)
+    print('A Simple Programme to Draw A Regular Polygon\n')
+
+    # Move repeated logic out into another more general function so we can reuse code in the future
+    num_sides = get_number(minimum=3, maximum=20, prompt='Please enter number of sides (between 3 and 20):')
+    side_length = get_number(minimum=1, maximum=100, prompt='Please enter the length for each side:')
+
+    polygon_name = get_polyname(num_sides)
+
+    # calculate internal angle of polygon
+    internal_angle = (num_sides - 2) * 180 / num_sides
+
+    print(
+        f'Okay, a {num_sides} sided polygon is called a {polygon_name} and it has an internal angles of {internal_angle} degrees.')
+    print(f'Lets draw a regular {polygon_name} with {side_length} long sides.')
+
+    draw_polygon(num_sides=num_sides, side_length=side_length, internal_angle=internal_angle, polygon_name=polygon_name)
+
+
+# A function that will keep asking until a number is supplied between min and max
+# A default value for prompt is used if not supplied
+def get_number(minimum, maximum, prompt='Please enter a number:'):
+    # Check whether function was supplied with sane min and max values, quit if not
+    if not int(minimum) or not int(maximum) or minimum > maximum:
+        raise ValueError('Please supply valid min and max integers')
+
+    # Loop infinitely until we reach return clause which exits function
+    while True:
+
+        # This block catches any errors and jumps to the 'except Exception' line below
+        try:
+            value = int(input(prompt + ' '))
+
+            #  Only finish if we have a valid value
+            if minimum <= value <= maximum:
+                return value
+            else:
+                print(f"Error - number not between {minimum} and {maximum}")
+        except Exception as e:
+            print(e)
+
+
+# returns polygone name for supplied number of sides in range 3-20
+def get_polyname(sides):
+    # dictionary of names "polynames"
+    polynames = {
+        3: "Triangle",
+        4: "Square",
+        5: "Pentagon",
+        6: "Hexagon",
+        7: "Heptagon",
+        8: "Octagon",
+        9: "Nonagon",
+        10: "Decagon",
+        11: "Hendecagon",
+        12: "Dodecagon",
+        13: "Triskaidecagon",
+        14: "Tetradecagon",
+        15: "Pendedecagon",
+        16: "Hexdecagon",
+        17: "Heptdecagon",
+        18: "Octdecagon",
+        19: "Enneadecagon",
+        20: "Icosagon",
+    }
+
+    return polynames[sides]
+
+# Holds the logic to draw a polygon using turtle
+def draw_polygon(num_sides, side_length, internal_angle, polygon_name):
+    turtle.screensize(4000, 4000)
+    turtle.hideturtle()
+    turtle.speed(speed=1)
+    turtle.bgcolor("grey")
+    turtle.pen(pencolor="blue", pensize=5)
+
+    for i in range(num_sides):
+        turtle.forward(side_length)
+        turtle.left(180 - internal_angle)
+
+    turtle.penup()
+    label_length = len(polygon_name)
+    turtle.goto(-label_length * 9 + label_length / 2, -60)  # start position for text
+    turtle.write(polygon_name, font=("Verdana", 25, "normal"))
+
+    # Wont close the screen until you click
+    turtle.Screen().exitonclick()
+
+
+# This will run the run() function only if we launched this script directly
+# Eg: it will not use the run() function if this file has been loaded as an import in another script
+if __name__ == '__main__':
+    run()