The two main methods of verification

Answer:
data check and double entry
Explanation:
Inputs have to be validated before allowing any kind of processing or operations to be performed on it. This is extremely important because , an unhandled wrong input might have the complete ability to crash a system. C++ has some good validation techniques that can be used to validate most kind of inputs. This post discusses some of the techniques and its shortcomings and what could be done to improve the quality of validation.