CPP stream input and output library

The most important of the three output streams

ostream
ofstream
ostringstream

Output stream predefined objects

cout standard output
cerr standard error output, no buffer, its content is sent to the output immediately.
cerr, similar to clog, but there is a buffer, when the output buffer is full.

Standard output commutation

ofstream fout("b.out");//自动打开文件，并且绑定到fout这个对象
streambuf*  pOld  =cout.rdbuf(fout.rdbuf());  cout的绑定到fout，而不是标准输入输出设备（显示器）
//…
cout.rdbuf(pOld);//绑定会原来的fout标准输入输出设备

Constructing the output stream object

ofstream class supports disk file output
If you specify a file name in the constructor, when the structure of the document file is opened automatically
```
ofstream myFile("filename");
```

You can use open member function to open a file after calling the default constructor

ofstream myFile; //声明一个静态文件输出流对象
myFile.open("filename");   //打开文件，使流对象与文件建立联系

Mode can be specified when the object is constructed, or open the file open
```
ofstream myFile("filename", ios_base::out | ios_base::binary);
```

Three types of file output stream member function

The actuating member function equivalent character.
Write operation member functions unformatted.
Other modifications and different flow states or manipulator insertion member function operator.

File output stream member function

open function

The flow associated with a particular disk file up.
You need to specify the open mode.

put function

Put a character to the output stream.

write function

A piece of the contents of memory to a file output stream

seekp and tellp function

Internal pointer file stream operation

close function

Close the stream associated with a file output disk file

Error handling function

Error handling when written to a stream