What is Quality?
Software quality is conformance to its explicit and implicit requirements. Quality attributes and requirements are relative and vary from person to person. Software testing ensures that the application under test conforms to all its business, technical design, functional, security, usability, and performance requirements.
Quality assurance
QA is a process-oriented activity that ensures the implementation of processes, procedures, and standards in an organization.QA’s main focus is on processes and procedures. An audit is an example of a QA activity.
Quality control
QC is a product-oriented activity verification of applications with respect to documented requirements. QC’s main focus is on the product. Testing is an example of a QC activity.