C ++ learning 14th-I/O Stream

1. I/O Stream

I/O functions are not part of the C ++ language; they come from the C ++ standard library iostream;

1) iostream Library:

2) stream

In C ++, I/O processing is a stream. A stream is a finite ordered byte, also known as a buffer pool.

There are two main types of stream: input stream and output stream.

3) Input and Output in C ++

IOS is the most common input and output base class; istream and ostream process the original class of input and output;

4) Standard stream in C ++

Mainly include: Cin, cout, cerr and clog

CIN is mainly for keyboard input, and the last three are mainly for display output.

Cerr is a non-buffered output that can process data types. Clog is a buffer type and Outputs Data in blocks.

2. input stream

Iostream is a very complex library. The most common section is discussed here.

All I/O functions are in the STD namespace;

1) extract Operators

> It is the input extraction operator. Generally, it processes built-in data types. You can reload it to process custom data types.

2) extraction and blank symbols

You can enter a single character through>, but the blank space is ignored. You can use cin. Get (CH) to write down the blank space;

You can also use cin. Get (BUF, length) to obtain the input of the specified length;

You can also use cin. Getline (BUF, length) to obtain the input of the specified length;

Input that is applied to string: Getline (CIN, STR ).

Some useful istream functions:

Ignore (), discard the first character in the stream; ignore (INT count), discard the first count character in the stream;

Peek (): reads a character from the stream, but does not remove it from the stream; upget () returns the character retrieved last time; putback (char ch) puts a character back.

To be continued ......

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