What is the difference between mechanical engineering and systems engineering?

Software Engineering (SE) deals with building and maintaining software systems. It is more software-oriented and has a greater emphasis on large software applications than Computer Engineering. It is more applied than Computer Science, placing greater emphasis on the entire software development process, from idea to final product. It is also more disciplined than Computer Science, applying more systematic practices to help ensure that products are reliable and safe.

Systems Engineering (SE) is an interdisciplinary field of engineering, that focuses on the development and organization of complex artificial systems. Systems Engineering integrates other disciplines and specialty groups into a team effort, forming a structured development process that proceeds from concept to production to operation and disposal. Systems Engineering considers both the business and the technical needs of all customers, with the goal of providing a quality product that meets the user needs.