Subj : Re: question on cin.putback() ..
To   : borland.public.cpp.borlandcpp
From : maeder
Date : Sun Jan 02 2005 05:22 pm

"Stan" <stan@yahoo.com> writes:

> #include <iostream>

Side note: The ISO C++ Standard asks you to also #include <istream>
and <ostream> for your program to have defined behavior.


> using namespace std;
>
> int main()
> {
>   cout << "input 'abcdef' :";
>   char c = cin.peek();
>   cin.putback('0');
>   char chararray[10];
>   cin >> chararray;
>   cout << chararray;
> }

These are 5 I/O operations, each of which can fail. You should check
for sucess of these operations before taking conclusions from entities
(apparently) read in.

if (std::cout << "input 'abcdef' :")
{
  std::istream::int_type const i(cin.peek());
  if (i==std::istream::traits_type::eof())
    // peek failed
  else
    if (std::cin.putback('0'))
    {
      // etc.
    }
    else
      // putback failed
}

.