std::istream::ignore

istream& ignore (streamsize n = 1, int delim = EOF);

Extract and discard characters

Extracts characters from the input sequence and discards them, until either n characters have been extracted, or one compares equal to delim.

The function also stops extracting characters if the end-of-file is reached. If this is reached prematurely (before either extracting ncharacters or finding delim), the function sets the eofbit flag.

Internally, the function accesses the input sequence by first constructing a sentry object (with noskipws set to true). Then (if good), it extracts characters from its associated stream buffer object as if calling its member functions sbumpc or sgetc, and finally destroys the sentry object before returning.

 

n

Maximum number of characters to extract (and ignore).
If this is exactly numeric_limits<streamsize>::max(), there is no limit: As many characters are extracted as needed until delim (or the end-of-file) is found.
streamsize is a signed integral type.

delim

Delimiting character: The function stops extracting characters as soon as an extracted character compares equal to this.
Note that the delimiting character is extracted, and thus the next input operation will continue on the character that follows it (if any).
If this is the end-of-file value (EOF), no character will compare equal, and thus exactly n characters will be discarded (unless the function fails or the end-of-file is reached).

 

// istream::ignore example
#include <iostream>     // std::cin, std::cout

int main () {
  char first, last;

  std::cout << "Please, enter your first name followed by your surname: ";

  first = std::cin.get();     // get one character
  std::cin.ignore(256,' ');   // ignore until space

  last = std::cin.get();      // get one character

  std::cout << "Your initials are " << first << last << '\n';

  return 0;
}

Possible output:

Please, enter your first name followed by your surname: John Smith Your initials are JS