Write the implementation (.cpp file) of the accumulator class of the previous exercise. the full specification of the class is: an data member named sum of type integer. a constructor that accepts no parameters. the constructor initializes the data member sum to 0. a function named getsum that accepts no parameters and returns an integer. getsum returns the value of sum. a function named add that accepts an integer parameter and returns no value. add increases the value of sum by the value of the parameter.