C++:io Buffer

1. C + + Each stream object maintains a buffer, which is essentially a character array for storing input and output sequences, and is described by three pointers (Begin_pointer,next_pointer,end_pointer), which are divided into full buffers by the refresh type. Row buffers and unbuffered. (see "C + + input and output stream and localization" for details)

2. Commonly used buffer functions

Function	Role
int Peek ()	Returns the next character in the buffer, and the pointer does not move back
void get (char ch)	Assigns the next character of the buffer to CH, and the pointer moves back
Char get ()	The next character of the buffer is taken out and returned, and the pointer moves back
void putback (char ch)	Puts a function that was previously read from the stream back into the buffer and inserts it into the current pointer position
IStream &ignore (streamsize num=1, int delim=eof)	Ignoring the next num characters or encountering Delim early end, Delim is also ignored
int sync ()	Clears the buffer associated with the stream, returns 0 for success, 1 for failure
istream& seekg (Streampos POS)	Sets the position of the input stream pointer to POS, POS is the absolute position
istream& seekg (Streamoff off, Ios_base::seekdir)	Setting the input stream pointer to the position relative to the path offset off, Ios_base::seekdir can take the following constants: Ios::beg (buffer start), ios::cur (current position), ios::end (end of buffer)
Streampos Tellg ()	Returns the current position of the pointer
ostream& SEEKP (Streampos pos) and ostream& SEEKP (Streamoff off, Ios_base::seekdir)	Similar to SEEKG for input stream objects
Streampos TELLP ()	Similar to TELLG for output stream objects

C++:io Buffer