Type-checking

Author: delmorallopez

type-checking.py

@@ -0,0 +1,97 @@
+# his code contains bugs related to types. They are bugs mypy can catch.
+
+# Read this code to understand what it’s trying to do.
+# Add type annotations to the method parameters and return types of this code.
+# Run the code through mypy, and fix all of the bugs that show up. 
+# When you’re confident all of the type annotations are correct, and the bugs are fixed, run the code and check it works.
+
+
+ 
+def open_account(balances, name, amount):
+    balances[name] = amount
+
+def sum_balances(accounts):
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_string(total_pence):
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = int(total_pence / 100)
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+# convert pounds to pence
+open_account(balances, "Tobi", int(9.13 * 100))   # 913 pence
+open_account(balances, "Olya", int(7.13 * 100))   # 713 pence
+
+total_pence = sum_balances(balances)
+total_string = format_pence_as_string(total_pence)
+
+print(f"The bank accounts total {total_string}")
+
+
+
+
+# When running mypy, I get the following errors:
+
+# type-checking.py:24: error: Missing positional argument "amount" in call to "open_account"  [call-arg]
+# type-checking.py:25: error: Missing positional argument "amount" in call to "open_account"  [call-arg]
+# type-checking.py:28: error: Name "format_pence_as_str" is not defined  [name-defined]
+# type-checking.py:34: error: Missing positional argument "amount" in call to "open_account"  [call-arg]
+# type-checking.py:35: error: Missing positional argument "amount" in call to "open_account"  [call-arg]
+# type-checking.py:38: error: Name "format_pence_as_str" is not defined  [name-defined]
+
+
+# To fix this code, I need to add type annotations and correct the function calls as follows:
+
+# wrong arguments to open_account, the function expects three arguments: balances, name, and amount.
+# one call passes a string "£7.13" instead of a number.
+# Wrong function name format_pence_as_str instead of format_pence_as_string.
+# To keep the program consistent (Everything in pence), convert pounds to pence when opening accounts.
+
+# Here is the corrected code:
+
+"""
+def open_account(balances, name, amount):
+    balances[name] = amount
+
+def sum_balances(accounts):
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_string(total_pence):
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = int(total_pence / 100)
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+# convert pounds to pence
+open_account(balances, "Tobi", int(9.13 * 100))   # 913 pence
+open_account(balances, "Olya", int(7.13 * 100))   # 713 pence
+
+total_pence = sum_balances(balances)
+total_string = format_pence_as_string(total_pence)
+
+print(f"The bank accounts total {total_string}")
+"""
+