Explain how Python does Compile-time and Run-time code checking?

Answer 1

Compile-time Checking

Imagine you're writing a recipe, and before you start cooking, you check if you've listed all the ingredients correctly. You might notice a mistake like "Add 300 flour"—where you forgot to write "grams" after "300." Fixing this before you cook saves you from making a mistake later.

Python does not do full compile-time checking like languages such as C++ or Java because it's an interpreted language. However, it does check basic syntax before running your code.

Example:

Incorrect code:

print("Hello World) # Missing closing quotation mark

Before running, Python will say:

SyntaxError: EOL while scanning string literal—basically, it caught the mistake in your recipe before you started cooking.

Run-time Checking

Now imagine you're following your recipe, but halfway through, you realize you wrote “bake for 60 minutes” when it should’ve been 30. Since you didn’t check earlier, you only realize the mistake while cooking—this is a run-time error.

In Python, errors like dividing by zero or accessing a missing file happen while the code is running because Python doesn’t check for these errors in advance.

Example:

Incorrect code:

x = 5 / 0 # Trying to divide by zero

Python starts running but suddenly stops and says:

ZeroDivisionError: division by zero—this is a run-time error because Python only catches it when it actually tries to do the math.

Key Differences

1. Compile-time errors: Caught before the code runs (like grammar errors in a recipe).
2. Run-time errors: Only appear while the code is running (like mistakes noticed while cooking).

Python lets you write code faster because it doesn’t force you to check everything before running, but that also means you need to be careful with possible errors while the code is running!