#ifndef UC_H_INCLUDED	// These include guards prevent errors from class
#define UC_H_INCLUDED	// redefinition if this header file is included twice.

#include <iostream>
#include <string>

// Avoid using namespace in a header file; that’s namespace pollution!

// This class UC (for UpperCase) illustrates member and non-member functions.
// It’s like the string class, but its data has no lowercase letters.
//
// The class is incomplete, but it shows how UC interacts with the other
// popular strings: C-style strings and std::string.
//
// It implements ctors, assignment, +, +=, and ostream insertion (<<).
//
// TODO:
// • string=UC;
// • UC=char, UC+=char, UC+char, char+UC
// • comparisons

class UC {
    using string = std::string; // local alias for std::string to ease typing
  public:
    // Constructors (alias ctors)
    UC();
    UC(const char *);
    UC(const string &);
    UC(const UC &);

    // Destructor
    ~UC();

    // Assignment operators
    // Return a reference to *this.
    UC& operator=(const UC &);

    // operator+=, which modifies this object.
    // It’s a sort of assignment operator, so return a reference to *this.
    UC& operator+=(const UC &);

    // Accessors to extract the underlying data.
    [[nodiscard]] const string& str() const;
    [[nodiscard]] const char *c_str() const;

  private:
    void upify();		// Convert data to uppercase.
    string data;		// The actual data for this object lives here.
};

// Here, operator+ must be a non-member function, because it might have
// a non-UC as the left operand, e.g.:
//	UC u("foo");
//	cout << "xyz" + u;

// operator+, which returns a fresh UC object.
// Return a temporary object by value.
UC operator+(const UC &, const UC &);

// This must be a non-member function.
std::ostream& operator<<(std::ostream &, const UC &);

#endif /* UC_H_INCLUDED */