A use case is a technique used in software engineering to describe and define the interactions between a user or a system and a product. It is a tool used to capture the functional requirements of a system and is an important part of the requirements gathering process in software development.
The use case defines a specific interaction between a user or system and the product being developed. It outlines the steps that are taken to achieve a specific goal or task, and identifies the inputs, outputs, and actors involved in the process. Use cases are typically presented in a diagram or table format, and may include descriptions, flow charts, and other visual aids to help illustrate the interactions.
Use cases are an important tool in software development because they help to ensure that the product being developed meets the needs of its intended audience. They provide a clear understanding of the user's needs and requirements, and help to ensure that the product is designed to meet those needs. Use cases also provide a way to test and validate the product's functionality and usability, and can help to identify potential issues and areas for improvement.
There are several types of use cases, including functional use cases, which describe how the system should behave under normal conditions; alternate use cases, which describe how the system should behave under different or unexpected conditions; and exception use cases, which describe how the system should handle errors or unexpected input.