c++ #ifndef LETTERBAG_H #define LETTERBAG_H

#include #include using namespace std;

// A LetterBag object represents a collection of letters in the range 'a' through 'z' // where we keep track of how many occurrences there are of each letter. // For example the LetterBag {'a', 'a', 'c', 'd', 'd', 'd'} means two a's one c and three d's. // Order doesn't matter so an object created by inserting 'b' then 'c' into an empty LetterBag is // equal to an object created by inserting 'c' then b' into an empty LetterBag. class LetterBag {

// output from the LetterBag object to the output stream, which letters in sorted order e.g. { d, d, f, z } friend ostream & operator<< (ostream & out, const LetterBag & let); // REQUIRED

// input to the LetterBag object from the input stream friend istream & operator>> (istream & in, LetterBag & let);

public: LetterBag() ; // no-parameter constructor for an empty LetterBag. // REQUIRED

// Use a string to initialize the object. Non letters are skipped. // Also, case is ignored, e.g. "ababa" and "ABABA" both mean "three a's and two b's" LetterBag(const string & s); // REQUIRED

// return the total number of letters int getCurrentSize() const; // REQUIRED

// insert ch into a copy of the current object and return the copy. // if ch is out of range, do nothing. 'A' and 'a' both count as an 'a' etc. LetterBag operator+(char ch) const;

// insert ch into the current object and return the current object // if ch is out of range, do nothing. LetterBag& operator+=(char ch); // REQUIRED

// remove all occurence occurrence of ch from the current object. // if ch is out of range or has count equal to zero do nothing. void removeAll(char ch);

// remove all occurrences of all letters. void clear(); // REQUIRED

// return the number of occurence of ch in the current object. int getFrequency(char c) const; // REQUIRED

// return a string with the letters in this object, in sorted order and lowercase. e.g. "ddfz" string toString() const; // REQUIRED

// return true iff the current object and other are equal. bool operator==(const LetterBag & other) const;

// return false iff the current object and other are equal. bool operator!=(const LetterBag & other) const;

private:

// you fill this part in depending on how you decide to store the letters.

};

#endif