Chapter 4 INPUT AND OUTPUT OBJECTS Chapter 4

Chapter 4 INPUT AND OUTPUT OBJECTS

Chapter 4 • The cout Object The cout object is used to display information to the monitor and is contained in the iostream. h and iostream header files.

Chapter 4 • Using the cout Object cout << item #1 << item #2 << item #3 << ·· << item #n;

Chapter 4 • The cout Output Stream Flows to the System Monitor

Chapter 4 • Using n and endl

Chapter 4 • The C++ Escape Sequences Used with cout a b n r t v \ ' ” ? Beep Backspace CRLF CR Horizontal tab Vertical tab Backslash Single quote Double quote Question mark

Chapter 4 • I/O Stream Manipulators setw(n) Sets field width to n setprecision(n) Sets floating-point precision to n setfill(n) Sets fill character to n ws Extracts white space characters endl Inserts a new line in the output stream, then flush Flushes the output stream

Chapter 4 • Setting the Field Width cout << setw(field width) << output item;

Chapter 4 • Generating Decimal Point Values cout. setf(ios: : fixed ); cout. precision(n);

Chapter 4 • Generating Left-Justified Values cout. setf(ios: : fixed); cout. setf( ios: : left);

Chapter 4 • Generating Currency Values cout. setf(ios: : fixed); cout. setf(ios: : showpoint); cout. precision(2);

Chapter 4 • Formatting Functions and Flags setf() unsetf() precision(n) fixed left right scientific showpoint showpos Sets a formatting flag. Unsets a formatting flag. Sets decimal output to n decimal places. Forces fixed decimal point output. Forces left justification within field. Forces right justification within field. Forces exponential, e, output. Forces a decimal point to be displayed along with trailing 0’s. (Used for currency outputs) Forces a + sign output for positive values.

Chapter 4 • The cin Object The cin object is used to read information from the keyboard and is contained in the iostream. h and iostream header files.

Chapter 4 • The cin Input Stream Flows from the Keyboard

Chapter 4 • Using the cin Object cin >> variable to be read; – Only one character is read at a time. – White space (blanks, tabs, new lines, carriage returns, etc. ) are ignored by cin when using the >> operator. However, white space can be read using different cin functions. – Numeric values can be read as characters, but each digit is read as a separate character.

Chapter 4 • Using get() and put() For Single Character Data cin. get(character variable); cout. put(character variable);

Chapter 4 • Reading Strings Using getline() getline(input stream, string object, 'delimiting character’); – To avoid a potential problem, use the line cin >> ws before the cin. getline() statement.

Chapter 4 • Opening an Input File ifstream fin(”file path"); • Opening an Output File ofstream fout(”file path"); • Opening an Input/Output File fstream finout(“file path”);

Chapter 4 • Processing an Open File if(!file. Object) { cout << "This file cannot be opened" << exit(1); }//END IF else { while (Read Data Item From Input File ) { //BEGIN LOOP Process data item. } //END LOOP }//END ELSE endl;