Add comments and move some functions to a class

computer-science-igcse-prereleases.py

@@ -210,24 +210,42 @@ def prerelease_047822_india_2020():
     payments_number = [1, 48, 80]
     print("%d payment(s) of Rs %.2f" % (payments_number[payment_option - 1], cost / payments_number[payment_option - 1]))
 
-def get_input(dict):
+# 2020 Cambridge iGCSE Computer Science prerelease (UK 1)
+class prerelease_098421_uk_1_2020:
+    def __init__(self):
+        prerelease_098421_uk_1_2020.run(self)
+    
+    # retrieve user input & validate it
+    def get_input(self, dict):
         tmp = None
+        # keep asking until input is valid
         while (not tmp):
+            # get input, strip spaces and convert to uppercase
             tmp = input().upper().strip()
+            # if input isn't a valid product code
             if (not tmp in dict.keys()):
+                # print error
                 print("Please enter a valid product code.")
-            device = None
+                # reset input to blank, so user is asked again
+                tmp = None
+        # return input
         return tmp
 
-def print_details(dict):
+    # print available options
+    def print_details(self, dict):
+        # for every item
         for item in dict.keys():
+            # display product code, price and description
             print("%s: $%.2f, %s" % (item, dict[item][0], dict[item][1]))
 
-def print_chosen(dict, item):
+    # print chosen option from dictionary and return cost
+    def print_chosen(self, dict, item):
+        # print product code and description
         print("%s: %s" % (item, dict[item][1]))
+        # return cost
         return dict[item][0]
     
-def prerelease_098421_uk_1_2020():
+    def run(self):
         # dictionaries of for items, prices and descriptions
         phones_dict = {"BPCM": (29.99, "Compact"),
                     "BPSH": (49.99, "Clam Shell"),
@@ -269,8 +287,8 @@ def prerelease_098421_uk_1_2020():
         while run:
             # get chosen device
             print("Choose an option:")
-        print_details(devices_dict)
-        device = get_input(devices_dict)
+            prerelease_098421_uk_1_2020.print_details(self, devices_dict)
+            device = prerelease_098421_uk_1_2020.get_input(self, devices_dict)
             # increase number of devices ordered
             devices += 1
 
@@ -278,17 +296,17 @@ def prerelease_098421_uk_1_2020():
             if (device in phones_dict.keys()):
                 # get chosen SIM
                 print("Choose an option:")
-            print_details(sims_dict)
-            sim_payg = get_input(sims_dict)
+                prerelease_098421_uk_1_2020.print_details(self, sims_dict)
+                sim_payg = prerelease_098421_uk_1_2020.get_input(self, sims_dict)
             
             # get chosen case
             print("Choose an option:")
-        print_details(case_dict)
-        case = get_input(case_dict)
+            prerelease_098421_uk_1_2020.print_details(self, case_dict)
+            case = prerelease_098421_uk_1_2020.get_input(self, case_dict)
 
             # get chosen charger(s)
             print("Which charger(s) would you like? Enter the codes for those you want with a space between them, or enter nothing to choose neither")
-        print_details(charger_dict)
+            prerelease_098421_uk_1_2020.print_details(self, charger_dict)
             # create array of chosen chargers
             chargers = input().upper().split(" ")
             # remove invalid product codes
@@ -299,21 +317,21 @@ def prerelease_098421_uk_1_2020():
             # if not first device, apply discount
             if (devices > 1):
                 # add cost of device to total
-            total += 0.9 * print_chosen(devices_dict, device)
+                total += 0.9 * prerelease_098421_uk_1_2020.print_chosen(self, devices_dict, device)
                 # record discount applied
-            saving += 0.1 * print_chosen(devices_dict, device)
+                saving += 0.1 * prerelease_098421_uk_1_2020.print_chosen(self, devices_dict, device)
             # if first device, don't apply discount
             else:
                 # add cost of device to total
-            total += print_chosen(devices_dict, device)
+                total += prerelease_098421_uk_1_2020.print_chosen(self, devices_dict, device)
             # if phone chosen, add cost of SIM to total
             if (device in phones_dict):
-            total += print_chosen(sims_dict, sim_payg)
+                total += prerelease_098421_uk_1_2020.print_chosen(self, sims_dict, sim_payg)
             # add cost of chosen case to total
-        total += print_chosen(case_dict, case)
+            total += prerelease_098421_uk_1_2020.print_chosen(self, case_dict, case)
             # add cost of chosen chargers to total
             for charger in chargers:
-            total += print_chosen(charger_dict, charger)
+                total += prerelease_098421_uk_1_2020.print_chosen(self, charger_dict, charger)
             # print subtotal
             print("Subtotal: $%.2f" % total)
             # ask if user want another device, and keep running if they do