What is Functional Testing and Non-Functional Testing? Give example in support your answer.

Functional Testing-It is based on customer requirements given by the customer and it works on how the software is expected to work in final output. It involves testing each feature of the software with giving various inputs and recording outputs and comparing them with expected results. It is carried out to validate software actions. It is easy to execute the functional testing manually .It helps to cover all the corner cases of the software testing by mutual agreement of the test strategy by tester through client interaction. It involves testing of APIs,UserInterfaces,server ports etc.It is performed before non-functional testing.
Examples of Functional Testing-Unit Testing,Smoke testing,User Acceptance,Integration Testing,Regression Testing
The Key aspects of Functional testing-
1)To cover all the requirements given by the customer.
2) Meet the production level requirement of the software.
3) Validate the behavior of the application in each and every aspect.

Non-Functional Testing-
It is a type of testing to test non-functional parameters of a software application. It is based on customer expectation. It is difficult to define the requirements for non-functional testing.It is done mostly to validate the performance specifications. It explains how the product works.A good example of non-functional testing would be to see how many people would be able login to the software.The key aspects of non-functional testing include-
1)To test the corner user aspects of the application.
2) To let the user test whatever he wants and confirm the operability.
3) To validate the all types of documentation and relevant info which are left in functional testing.
4)To let the customer and test what additional scenarios, he wants too test.
Examples-Scalibility Testing,Stress and Robustness Testing.