//letter.cpp
#include"letter.h"

//even though private, the static data must
//be given initial values globally.
//It may not be modified this way later.
int Letter::lowerToUpper='A'-'a';
Letter::style Letter::theCase=lower;

void Letter::setStyle(style s)
  { theCase=s;}

void Letter::setLetter(char x)
  {
  if ('A'<=x && x<='Z')
    c=x-lowerToUpper;
  else c=x;
  }

char Letter::getLetter()
  {
  if ('a'<=c && c<='z')  //c is a letter
    return c + theCase*lowerToUpper;
  return c;
  }

bool Letter::operator==(Letter right)
  {return c==right.c;}

//Since operator<< and operator>> are not member functions
//there is no Letter:: in front.
//operator<<, as defined, doesn't need to be a friend.
ostream& operator<<(ostream& out, Letter let)
  {
  out << let.getLetter();
  return out;
  }

istream& operator>>(istream& in, Letter& let)
  {
  in >> let.c;
  if ('A'<=let.c && let.c<='Z')
    let.c=let.c-let.lowerToUpper;
  return in;
  }