13.4.2. istream Member Functions peek, putback and ignore
The ignore member function of
istream reads and discards a designated number of characters (the default is one) or terminates upon encountering a designated delimiter (the default is
EOF, which causes
ignore to skip to the end of the file when reading from a file).
The putback member function places the previous character obtained by a
get from an input stream back into that stream. This function is useful for applications that scan an input stream looking for a field beginning with a specific character. When that character is input, the application returns the character to the stream, so the character can be included in the input data.
The peek member function returns the next character ...