Final answer:
Software testers are needed to ensure the overall quality and functionality of the software. They help identify bugs and performance problems, perform different types of testing, and offer an independent evaluation of the software.
Step-by-step explanation:
Software testers are needed even if developers test their code because they serve a different purpose in the software development process. While developers focus on writing and testing their code, software testers have a broader perspective and are responsible for ensuring the overall quality and functionality of the software.
Software testers help identify bugs, issues, and performance problems that may have been overlooked by the developers. They also perform various types of testing, such as unit testing, integration testing, and user acceptance testing, to validate the software under different scenarios and ensure its reliability.
In addition, software testers serve as an objective third-party, providing an independent evaluation of the software. They bring a fresh perspective and can identify potential usability issues or areas for improvement that may be missed by the developers who are closely involved in the code development process.