What is the output of 'S999' in numeric formatting?

In numeric formatting, 'S999' indicates that the value can represent both positive and negative numbers. The 'S' prefix is often used to denote a signed numeric value, which means that the output can include both positive and negative representations. This format is essential in applications where the sign of the number is meaningful, such as financial reporting or data analysis.

The use of '999' means that it expects a numeric input, while the 'S' signifies that the number can be either positive or negative based on the value assigned. This flexibility is crucial for accurate data representation, particularly when working with financial figures or statistical data that requires differentiation between gains and losses.

Thus, the reasoning behind this format supports the output being classified as capable of representing both positive and negative numbers.