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Chapter 4 INPUT AND OUTPUT OBJECTS PowerPoint Presentation
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Chapter 4 INPUT AND OUTPUT OBJECTS

Chapter 4 INPUT AND OUTPUT OBJECTS

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Chapter 4 INPUT AND OUTPUT OBJECTS

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  1. Chapter 4INPUT AND OUTPUT OBJECTS

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

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

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

  5. Chapter 4 • Using \n and endl

  6. 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

  7. Chapter 4 • I/O Stream Manipulatorssetw(n) Sets field width to nsetprecision(n) Sets floating-point precision to nsetfill(n) Sets fill character to nws Extracts white space charactersendl Inserts a new line in the output stream, thenflush Flushes the output stream

  8. Chapter 4 • Setting the Field Widthcout << setw(field width) << output item;

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

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

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

  12. Chapter 4 • Formatting Functions and Flagssetf() 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.

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

  14. Chapter 4 • The cin Input Stream Flows from the Keyboard

  15. Chapter 4 • Using the cin Objectcin >> 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.

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

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

  18. Chapter 4 • Opening an Input Fileifstream fin(”file path"); • Opening an Output Fileofstream fout(”file path"); • Opening an Input/Output Filefstream finout(“file path”);

  19. Chapter 4 • Processing an Open Fileif(!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