Explain the use of Go's defer statement for stacking function calls in LIFO order?

The defer statement is used to schedule a function call to be executed after the current function completes, but before the function returns. The function call is executed in LIFO order, meaning that the last deferred function call is executed first, followed by the second-to-last, and so on, until all the deferred function calls have been executed.

The **defer** statement is often used for cleaning up resources, such as closing files or releasing memory, at the end of a function, regardless of whether the function completes normally or panics. By deferring the cleanup function call, it ensures that the cleanup code is always executed, even if an error occurs or the function panics.

Here's an example that shows how to use the **defer** statement to schedule a cleanup function call at the end of a function:

func readConfigFile(filename string) (*Config, error) {
    f, err := os.Open(filename)
    if err != nil {
        return nil, err
    defer f.Close() // schedule the file close for after the function returns

    // read the config file and return a Config object
    // ...

In this example, the **os.Open** function is called to open a file, and the **defer** statement schedules the file's **Close** method to be called after the **readConfigFile** function returns, regardless of whether it returns an error or not.

Note that deferred function calls are only executed if the enclosing function completes normally (i.e., without panicking). If the enclosing function panics, any deferred function calls are still executed, but only after the panic has been handled by the **recover** function.

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