Final answer:
Python Code Template:
```python
def calculate_retail_price():
try:
# Get input from the user
wholesale_cost = float(input("Enter the item's wholesale cost: $"))
markup_percentage = float(input("Enter the markup percentage: "))
# Validate input
if wholesale_cost < 0 or markup_percentage < 0:
raise ValueError("Input values must be non-negative.")
# Calculate retail price
markup_amount = wholesale_cost * (markup_percentage / 100)
retail_price = wholesale_cost + markup_amount
# Display the result
print(f"The retail price of the item is: ${retail_price:.2f}")
except ValueError as e:
print(f"Error: {e}")
# Call the function to execute the program
calculate_retail_price()
```
Step-by-step explanation:
This Python program prompts the user for the wholesale cost and markup percentage of an item. It then calculates the retail price using the formula: `Retail Price = Wholesale Cost + Markup Amount`. The program also includes input validation to ensure that both the wholesale cost and markup percentage are non-negative.
If the user enters invalid data, the program catches the `ValueError` and prints an error message. The final retail price is displayed with a precision of two decimal places. The code structure promotes readability and modularization, making it easy to understand and maintain.