Q-Difference between functional testing and non functional testing

A-Functional testing is a type of software testing where each functions and features of the software are tested to know whether the functionalities are workings as expected or not.
example: new modules have been added to the present build, need to perform regression testing in order to check whether other aspects of the build has been affected by this module or not.

Non functional testing is a type of testing where the non functional aspects of the software are tested such as load, performance, speed, usability etc.
example: thousands of people trying to login at the same time, in order to test this load testing can be performed.

Types of functional testing are unit testing, integration testing, system testing, smoke testing, regression testing, etc.

Types of non functional testing are performance testing, load testing, stress testing, security testing, etc.

Functional testing is done based on customer requirements and non functional is focused on customer expectations. Functional testing can be done manually where as it is difficult to do non functional testing without the help of tools.

Both functional and non functional are equally important in order to deliver a finished and quality product to the clients/customers/end users.