feat: add input validation to temperature conversion exercise

ch06-functions-and-loops/3-challenge-convert-temperatures.py

@@ -2,37 +2,40 @@
 # Solution to challenge
 
 
+def get_numeric_input(prompt):
+    """Prompt the user until a valid numeric input is entered."""
+    while True:
+        try:
+            return float(input(prompt))
+        except ValueError:
+            print("Invalid input. Please enter a numeric value.")
+
+
 def convert_cel_to_far(temp_cel):
     """Return the Celsius temperature temp_cel converted to Fahrenheit."""
-    temp_far = temp_cel * (9 / 5) + 32
-    return temp_far
+    return temp_cel * (9 / 5) + 32
 
 
 def convert_far_to_cel(temp_far):
     """Return the Fahrenheit temperature temp_far converted to Celsius."""
-    temp_cel = (temp_far - 32) * (5 / 9)
-    return temp_cel
+    return (temp_far - 32) * (5 / 9)
+
 
 
 # Prompt the user to input a Fahrenheit temperature.
-temp_far = input("Enter a temperature in degrees F: ")
+temp_far = get_numeric_input("Enter a temperature in degrees F: ")
 
 # Convert the temperature to Celsius.
-# Note that `temp_far` must be converted to a `float`
-# since `input()` returns a string.
-temp_cel = convert_far_to_cel(float(temp_far))
+temp_cel = convert_far_to_cel(temp_far)
 
 # Display the converted temperature
 print(f"{temp_far} degrees F = {temp_cel:.2f} degrees C")
 
-# You could also use `round()` instead of the formatting mini-language:
-# print(f"{temp_far} degrees F = {round(temp_cel, 2)} degrees C"")
-
 # Prompt the user to input a Celsius temperature.
-temp_cel = input("\nEnter a temperature in degrees C: ")
+temp_cel = get_numeric_input("\nEnter a temperature in degrees C: ")
 
 # Convert the temperature to Fahrenheit.
-temp_far = convert_cel_to_far(float(temp_cel))
+temp_far = convert_cel_to_far(temp_cel)
 
 # Display the converted temperature
 print(f"{temp_cel} degrees C = {temp_far:.2f} degrees F")