Testing and debugging are essential aspects of software development that ensure the quality and reliability of a program. Testing involves verifying the functionality of code by systematically checking for expected and unexpected results, while debugging is the process of identifying and fixing errors or defects in the code.

Testing allows developers to catch bugs early in the development cycle, reducing the chances of issues occurring in production. It helps identify flaws in program logic, improper implementation of algorithms, or incorrect handling of edge cases.

Debugging, on the other hand, focuses on pinpointing and resolving problems that arise during testing or after deployment. It involves isolating the root cause of an issue, stepping through code to identify the code segment responsible for the error, and implementing necessary fixes.

By performing thorough testing and efficient debugging, developers can ensure their software functions correctly, performs optimally, and delivers a positive user experience.