difference between qa and testing

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.
Quality Control: A set of activities designed to evaluate a developed work product.
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.)

- QA is planned and systematic way to evaluate quality of process used to produce a quality product.

- QC in software industry is evaluating software product, find the defects & suggest improvements.

Quality Assurance - Prevention of faults by inspecting & testing the process

Quality Control - Detection of faults by inspecting & testing the product