2. FILE OPEN MODES

3. File open modes n ios::app n ios::ate n ios::binary n ios::in n ios::out n ios::trunc n ios::nocreate n ios::noreplace

4. ios::app Write all output to the end of file, no matter how you set the seekp pointer.  ofstream: open file, write data to the end of file.  ifstream: open file, read data from file.  fstream: open file, write data to the end of file, BUT cannot read data from file. If the file does not exist, the program will create a new file.

5. Example Before Alex Zhao Andrew Nguyen Vincent Tran After Alex Zhao Andrew Nguyen Vincent Tran Tyler Price fstream File (“myFile.txt”, ios::app); File.seekp (0); File << “Tyler Price”;

6. ios::ate Open a file for output and move pointer to the end of file. Data can be write anywhere in the file.  ofstream: open file, write data to the end of file.  ifstream: open file, but CANNOT read data  fstream: CANNOT open file. If the file does not exist, the program will create a new file.

7. Example Before Alex Zhao Andrew Nguyen Vincent Tran After Tyler PriceAndrew Nguyen Vincent Tran fstream File (“myFile.txt”, ios::ate); File.seekp (0); File << “Tyler Price”;

8. ios::binary Open a file for binary input and output.  ofstream: open file, discard the file’s content, write data to the file.  ifstream: open file, discard the file’s content.  fstream: CANNOT open file. If the file does not exist, the program will create a new file.

9. Example Before Alex Zhao Andrew Nguyen Vincent Tran After Tyler Price ostream File (“myFile.dat”, ios::binary); File.write (interpret_cast (&data), sizeof (data));

10. ios::in Open a file for input.  ofstream: not support ios::in.  ifstream: open file, read data from file.  fstream: open file, read data from file. If the file does not exist, the program will create a new blank file.

11. ios::out Open a file for output.  ofstream: open file, discard the file’s content, then write data to the file.  ifstream: not support ios::out.  fstream: open file, discard the file’s content, then write data to the file. If the file does not exist, the program will create a new file.

12. Example Before Alex Zhao Andrew Nguyen Vincent Tran After Tyler Price ostream File (“myFile.txt”, ios::out); File << “Tyler Price”;

13. ios::trunc Discard the file’s contents if it exists.  ofstream: open file, discard the file’s content, then write data to the file.  ifstream: open file, discard the file’s content.  fstream: open file, discard the file’s content, then write data to the file. If the file does not exist, the program will create a new file.

14. ios::nocreate  ofstream: open file, discard the file’s content, then write data to the file.  ifstream: open file, read data from file.  fstream: cannot open file. If the file does not exist, the open operation fails.

15. ios::noreplace If the file exists, the open operation fails.  ofstream: create a file, then write data to the file.  ifstream: create a blank file.  fstream: cannot open file.