Write a class stringset. a stringset object is given a series of up to 10 string objects. it stores these strings (or a reference to them, to be precise) and can perform limited calculations on the entire series. the stringset class has the following specification: // an instance variable of type string[] // an int instance variable that indicates the number of string objects that the stringset currently contains // a single no-argument constructor // a mutator that adds a string newstr to the stringset object. if adding the new string to the string[] succeeds, the add method returns true. // if adding the new string to the string[] fails (maybe the array is already full, for example), add returns false. boolean add(string newstr)