QA is the qulity we are assuring for a product in the 
entire lifecycle 

QC is like ,to achive QA what are the steps/process areas 
we need to follow

difference between QA and QC:
Quality Assurance(QA):
   
   QA is a Verification process like reviews.

Quality Control(QC):

   QC is a Validation process like testing the product.

QA means testing process along with reviews(QA Engg.)

Qc checks and control the QA activities(Audit team)

Quality ASsurance Is Preventive Method.It Is Used To
Identify The Weekness In The Project.It Is Process Oriented.
Quality Control Is Detective Method.It Is Product
Oriented.QC Going To Check Whether The Customers Staisfied
Their Needs Or Not

Quality control is used to verify that deliverables are of 
acceptable quality and that they are complete and correct.
Quality Assurance: Quality Assurance is that set of 
activities that are carried out to set standards and to 
monitor and improve performance so that the care provided 
is as effective and as safe as possible

verification                       validation
process oriented                     product oriented
prevetion based                    detection based

QUALITY ASSURANCE
1.Prevention Based
2.Process Oriented
3. Organisation level
4. Phase Building Activity

QUALITY CONTROL
1. Detection Based
2. Product Oriented
3. Producer/Project Level
4.Phase End Activity

QA:
Means the quality assurance He performs testing on the input
and out put of the task in terms of documents. he involves in 
all the stages of sdlc

Qc: 
Means the quality control .He involves in testing . it is
done after coding.