PREFINALS | Streams | Event-Driven Programming

Streams

represent a source that provides a sequence of bytes, such as a file, an input/output (I/O) device, an interprocess communication pipe, or a TCP/IP socket.

Output streams

It refers to a printer, remote server location, or a printer where the data is written.

Input streams

It refers to a file or any source where the data can be read and assigned to the memory variables in the program.

System.IO

This namespace contains classes that allow to write and read files. This namespace needs to be included in all programs that use streams.

Byte-oriented

All files are ____ ______, meaning the data is written or read into the files in terms of bytes.

FileStream

It is a class that is used to create a byte-oriented stream attached to a file.

FileStream(string filename,FileMode mode)

The code to be used for creating a FileStream object is:

Mode

The _ parameter specifies how the file needs to be opened.

FileMode.Create

It creates a new output file, which will be overwritten if a file already exists.

FileMode.CreateNew

It creates a new output file that is not existing.

FileMode.Open

It opens an existing file.

FileMode.OpenOrCreate

It opens an existing. If not, it creates a new one.

FileMode.Truncate

It opens an existing file and truncates the content that already exists.

FileStream Constructor

The __ is used to open a file that has access to read or write.

FileMode.Create, FileMode.CreateNew, FileMode.Open, FileMode.OpenOrCreate, FileMode.Truncate

The options for FileMode are as follows: HINT: C CN O OOC T

ReadByte()

This method reads a single byte from a file and returns as an integer value.

Read()

This method reads the specified number of bytes from a file into an array.

WriteByte()

It writes the specified byte into the file.

Write()

It writes an array of bytes into the file.

Flush()

This method instantly writes the data into the file.

void Close()

This method closes the file, releasing the system resources that are allocated to it

ReadByte(), Read(), WriteByte(), Write(), Flush(), void Close()

This class also contains the following methods to perform read and write operations: HINT: RB R WB W F C

Seek()

To access a file randomly, position the file pointer inside the file at the required location. A file pointer determines the location of the next read/write operation to take place on the file. The method used to relocate the file pointer in the file is ____ (Harwani, 2015, p. 462). ______ is a method that allows setting the file position indicator of file pointer to the preferred location in the file.

long Seek(long n, SeekOrigin location)

The syntax for Seek() is:

Position

The file pointer can get or set the position using the _ property of Stream class.

bool CanRead

It returns true if the stream can be read.

bool CanSeek

It returns true if the stream supports position requests.

bool CanTimeout

It returns true if the stream can time out.

bool CanWrite

It returns true if the stream can be written.

long length

It contains the size of the stream.

int ReadTimeout

It indicates the time before a timeout occurs for read operations.

int WriteTimeout

It indicates the time before a timeout occurs for write operations.

bool CanRead, bool CanSeek, bool CanTimeout, bool CanWrite, long length, int ReadTimeout, int WriteTimeout

Aside from the Position property, these properties are commonly used:HINT: BCR BCS BCT BCW LL IRT IWT

StreamWriter, StreamReader

To perform a character-based file for managing text files, use character streams to read and write into the file. Since, internally, each file consists of bytes, the FileStream is wrapped inside either a or a __. These classes automatically convert a byte stream into a character stream, and vice versa.

StreamWriter

It writes characters to a stream and contains several constructors.

SteamWriter(Stream stream)

It is used to create a character-based output stream.

StreamWriter(string fileName)

It is used to open a file directly.

SteamWriter(Stream stream), StreamWriter(string fileName)

StreamWriter writes characters to a stream and contains several constructors, such as the following:

Close(), Flush, Write, WriteLine

The StreamWriter class contains the following common methods: HINT: C F W WL

Close()

It closes the file.

Flush()

It instantly saves the file content from buffer to memory

Write()

Using a File stream class, this writes into the specified file.

WriteLine()

Line by line, it writes into a file.

StreamReader

This is a class that reads characters from a byte stream. StreamReader(Stream stream)

StreamReader(string fileName)

It specifies the name of the file to open.

StreamReader(Stream stream), StreamReader(string fileName)

StreamReader defines the following constructors:

Flush(), Close(), Read(), ReadLine(), ReadToEnd(), Peek(), Seek()

The StreamReader class also contains the following common methods:

Flush()

From buffer to memory, it instantly saves the file content.

Close()

It closes the file and is mandatory to this class.

Read()

From the file stream, it reads the content.

ReadLine()

From the given file stream, it reads the content line by line.

ReadToEnd()

From the current location until the end of the stream, it reads all characters.

Peek()

It returns the value in the stream without moving the file pointer.

Seek()

Sets the file pointer at the desired position in a file.