Testing: The process of executing a system with the intent of finding defects. Note that the "process of executing a system" includes test planning prior to the execution of the test cases. Testing has further type like black box testing ,white box testing and so on. I would like some explain about the testing type. Black box testing:- In this testing have no idea how to come output. In testing just enter the value and check the corresponding output. like i want print the two Table 2,4,6,8,10. Enter the 2 number and select the last point 10. print the all value one by one. if all values are print then every thing is ok other wise some error. Quality Assurance: A set of activities designed to ensure that the development and/or maintenance process is adequate to ensure a system will meet its objectives.