2.10 Robust Code

Robust code is designed to cope with unexpected situations without crashing.

Characteristics:

• Handles unexpected inputs
• Handles unexpected termination
• Produces specific and meaningful error messages

Robust programs check input before using it.

Python example:

try:
    age = int(input("Enter your age: "))
    print("Age entered:", age)
except ValueError:
    print("Error: Please enter a whole number")
        

Programs can fail due to missing files or unavailable resources.

Python example:

try:
    file = open("data.txt", "r")
    print(file.read())
    file.close()
except FileNotFoundError:
    print("Error: File not found")
        

Debugging is the process of:

• Locating errors in code
• Correcting errors in code

When used: When code behaves unexpectedly or crashes.

Debugging improves robustness by:

• Identifying weaknesses in logic
• Ensuring unexpected cases are handled
• Preventing crashes and data loss

Robust solutions are the result of careful debugging.

Errors may be identified through error messages or incorrect output.

Python example:

numbers = [10, 20, 30]

print(numbers[3])
        

Error: Index out of range.

Once identified, code must be corrected and tested.

Corrected Python example:

numbers = [10, 20, 30]

print(numbers[2])
        

The index has been changed to a valid value.