Which data validation method provides an error message when a validation rule has been broken?

y and z are user-defined objects and the += operator is an overloaded member function. The operator is overloaded such that y += z adds z and y, then stores the result in y. Which of the following expressions is always equivalent to y += z?

a. y = y operator+= z b. y.operator+=( z ) c. y = y + z d. y operator+=( y + z )

Why would you use the append() method? Provide an example.

What will be an ideal response?