rust armanazi error cannot use the `?` operator in a function that returns `()`

The error message "cannot use the ? operator in a function that returns ()" in Rust indicates that you are trying to use the ? operator in a function that has a return type of (). The ? operator is used for error handling and is typically used in functions that return a Result type.

In Rust, the Result type is an enum that represents either a successful value (Ok) or an error value (Err). The ? operator is used to propagate errors in a concise manner. It works by returning the error immediately if it is Err, or unwrapping the value if it is Ok.

However, the ? operator can only be used in functions that have a return type of Result or a type that implements the Try trait. Functions that return () (also known as unit type) do not allow the use of the ? operator because there is no meaningful error handling to be done.

To resolve this error, you can either change the return type of your function to Result<(), ErrorType> if you want to handle errors, or you can remove the ? operator if error handling is not necessary in your function.

Here's an example of a function that returns Result<(), Error> and uses the ? operator for error handling:

fn example_function() -> Result<(), Box<dyn std::error::Error>> {
    // Some code that can return an error
    let result = some_operation()?;

    // Rest of the function logic
    Ok(())
}

And here's an example of a function that returns () and does not use the ? operator:

fn example_function() {
    // Some code without error handling
    let result = some_operation();

    // Rest of the function logic
}