Quality is delighting customers
Quality Assurance: Quality Assurance involves process-oriented activities. It ensures avoiding errors in the process used to make Software application. So the defects do not arise when the software application is developed.
Quality control: quality control involves product-oriented activities. It runs the program or code to identify the flaws in the software application.
You have posted a really Nice Question about QA and QC. Many people have this myth that QA and QC are same, however, both of these are different. As per quality assurance services below is one-liner definition for both:
QA makes sure that the techniques, processes, approaches and methods designed for the projects are correctly implemented. It's a proactive process and preventive in nature.
QC makes sure that the techniques, processes, approaches and methods designed in the project are correctly following.