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

The C++ Escape Sequences Used with cout Chapter 4 The C++ Escape Sequences Used with cout \a Beep \b Backspace \n CRLF \r CR \t Horizontal tab \v 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);

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

Using the cin Object cin >> variable to be read; 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”);

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