//: C10:StaticVariablesInfunctions.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
#include "../require.h"
#include <iostream>
using namespace std;

char oneChar(const char* charArray = 0) {
  static const char* s;
  if(charArray) {
    s = charArray;
    return *s;
  }
  else
    require(s, "un-initialized s");
  if(*s == '\0')
    return 0;
  return *s++;
}

char* a = "abcdefghijklmnopqrstuvwxyz";

int main() {
  // oneChar(); // require() fails
  oneChar(a); // Initializes s to a
  char c;
  while((c = oneChar()) != 0)
    cout << c << endl;
} ///:~