Make last character got from stream available again.
  Decrements by one the get pointer for the input buffer.

Parameters.

none

 

Return Value.
  The function returns *this

Example.

// read a 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<charT,traits>):

basic_istream& unget ( );

See also.
  get, putback,
  istream class