What is the role of the defer operator in Go and what are its advantages?

The defer operator in Go is used to postpone the execution of a function until the surrounding function exits (usually for resource cleanup or final actions).

Advantages of defer:

• Ensures the code runs at the end of the function, even if the function exits with an error or panic.
• Improves code readability by allowing resource release to be written next to their allocation.
• Helps avoid code duplication for cleanup in different parts of the function.

Example:

func readFile() error {
    file, err := os.Open("file.txt")
    if err != nil {
        return err
    }
    defer file.Close() // the file will be closed when the function exits

    // work with the file
    return nil
}

Here, file.Close() will be called automatically when readFile exits, regardless of how the function terminates.