istream& unget ( );

Decrement get pointer

Decrements the internal get pointer by one, making the last character extracted from the input sequence available again as the next character to be read from the stream.

The function effectively calls the sungetc member function of the streambuf object associated to the stream.

A subsequent call to member gcount will return zero.

Parameters

Return Value

Errors are signaled by modifying the internal state flags:

Additionaly, in any of these cases, if the appropriate flag has been set with member function ios::exceptions, an exception of type ios_base::failure is thrown.

Example

// read entire file into memory
#include <iostream>
using namespace std;

int main () {
  char c;
  int n;
  char str[256];

  cout << "Enter a number or a word: ";
  c = cin.get();

  if ( (c >= '0') && (c <= '9') )
  {
    cin.unget();
    cin >> n;
    cout << "You have entered number " << n << endl;
  }
  else
  {
    cin.unget();
    cin >> str;
    cout << " You have entered word " << str << endl;
  }

  return 0;
}

Basic template member declaration

basic_istream& unget ( );

See also