/* Code for exercise 7.11. |  | "C++ Solutions--Companion to The C++ Programming Language, Third Edition" | by David Vandevoorde; Addison-Wesley 1998; ISBN 0-201-30965-3. | | Permission to use, copy, modify, distribute and sell this software | and its documentation for any purpose is hereby granted without fee. | The author makes no representations about the suitability of this | software for any purpose.  It is provided "as is" without express or | implied warranty. `----------------------------------------------------------------------*/#include <assert.h>#include <stdarg.h>#include <iostream.h>#include <stdexcept>void error(char const *fmt, ...) {   assert(fmt);   va_list p;   va_start(p, fmt);   for (char const *s = fmt; *s; ++s)      if (*s!='%')         std::cerr.put(*s);      else         switch (*(++s)) {         case '%': std::cerr.put('%'); break;         case 's': std::cerr << va_arg(p, char const*); break;         case 'c': std::cerr << va_arg(p, char); break;         case 'd': std::cerr << va_arg(p, int); break;         default: throw std::domain_error(std::string ("panic"));         }   va_end(p);}int main() {   error("A string \"%s\", a single character \'%c\', an integer %d\n"         "and a percent-symbol \'%%\'.\n",         "Hello World", '$', 12345);   return 0;}