Write a class definition of a class named value with the following:
an integer variable that holds the value
a boolean variable that keeps track if the value has been modified
a constructor accepting a single integer parameter
a constructor with no parameters
a method setval that accepts a single parameter,
a boolean method, wasmodified that returns true if setval was ever called for the object.
a method getval that returns an integer value as follows: if setval has ever been called, it getval returns the last value passed to setval.
otherwise if the "single int parameter" constructor was used to create the object, getval returns the value passed to that constructor.
otherwise getval returns 0.