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Here buffer is the address of a piece of memory, used to store or read data. read (char * buffer, streamsize size ) //Read size characters from the file to the buffer.write (char * buffer, streamsize size ) //Read size characters from the buffer and write them to the file.This is the most common: if calling any of the above functions returns true, this function returns false. Returns true if the read file reaches the end of the file. In addition to fail() returning true in the same situation as bad(), it also returns true when there is a format error, such as when you want to read an integer and get a letter. For example: when we want to write to a file that is not opened for writing, or when the device we want to write has no free space. Returns true if an error occurs during reading and writing. The result is output on the screen: HELLO WORLD! You can use "or" to connect the above attributes, such as ios::out|ios::binary ios::trunc: If the file exists, set the file length to 0.ios::noreplace: do not overwrite the file, so if the file exists, it fails when opening the file.ios::nocreate: The file is not created, so the file fails to open when it does not exist.ios::out: The file is opened in output mode (the memory data is output to the file).ios::in: The file is opened as input (file data is input to the memory).See above for the difference between the two methods ios::binary: Open the file in binary mode, the default mode is text mode.ios::ate: After the file is opened, locate to the end of the file, ios:app contains this attribute.The way to open the file is defined in the class ios (the base class of all streaming I/O classes), and the commonly used values ​​are as follows: Open the file prot The attributes of the file to open Parameters: filename The name of the file to be operated

Void open(const wchar_t *_Filename, ios_base::openmode mode = ios_base::in | ios_base::out,int prot = ios_base::_Openprot) Void open (const char * filename,ios_base::openmode mode = ios_base::in | ios_base::out )