What does the stream position signify when a file is opened in 'a' mode?

When a file is opened in 'a' mode, which stands for 'append', the stream position is set to the end of the file. This means that any data written to the file will be added after the existing content, instead of overwriting it. This behavior allows for new information to be appended seamlessly, making 'a' mode particularly useful for logging or updating files without losing pre-existing data.

By starting the write position at the end of the file, 'a' mode ensures that your new output does not overwrite any existing data, which is crucial when you want to preserve previous entries. This effectively allows for a continuous addition of data, maintaining the order in which entries are made. Additionally, regardless of the file size, the behavior remains consistent—newly written data will always be forthcoming at the end.