Streams and Files
- 1. Streams and Files: Chapter 12: Ms. Munazza Mah Jabeen Assistant Professor of Computer Science
- 2. Stream Classes: • A stream is a general name given to a flow of data. iostream standard library provide cin and cout methods for reading from standard input and writing to standard output respectively. • To read and write from a file we need another standard C++ library called fstream, which defines three new data types: • ofstream • ifstream • fstream • To perform file processing in C++, header files <iostream> and <fstream> must be included in your C++ source file • The extraction operator >> is a • member of the istream class, and the insertion operator << is a member of the ostream class.
- 3. Opening / Closing a File: • A file must be opened before you can read from it or write to it. Either the ofstream or fstream object may be used to open a file for writing and ifstream object is used to open a file for reading purpose only. standard syntax for open() function: void open(const char *filename, ios::openmode mode) To open a file in write mode or truncate it if it exists ofstream outfile; outfile.open("file.dat", ios::out | ios::trunc ); fstream afile; afile.open("file.dat", ios::out | ios::in ) • To close a File: standard syntax for close() function void close();
- 4. Reading / Writing a File: • In order to write to a file we use the stream insertion operator (<<) just sending output to the screen. The only difference is that you use an ofstream or fstream object instead of the cout object. • To read information from a file use the stream extraction operator (>>) just like input information from the keyboard. The only difference is that you use an ifstream or fstream object instead of the cin object.
- 5. Strings with Embedded Blanks:
- 6. Object I/O:
- 7. I/O with Multiple Objects:
- 8. Error Handling in File I/O: