White Spaces

1. White Spaces Space Tab Next line …

2. Input Operator >> cout << "What is your input: "; cin >> theInput; // Operator >> will ignore white spaces // before reading // Operator >> will stop at white spaces // after have read any value // Input: -50.5 50 // What is the value of theInput? // Depending on the type of theInput // But the spaces before “-50.0” will be ignored.

3. Type char char theInput; cout << "What is your input: "; cin >> theInput; // Input: -50.5 50 // Q: What is the value of theInput? // A: _____ // ‘-’ // Not space before ‘-’

4. Type integer int theInput; cout << "What is your input: "; cin >> theInput; // Input: -50.5 50 // Q: What is the value of theInput? // A: _____ // -50 // stop at ‘.’, which cannot be part of int

5. Type float float theInput; cout << "What is your input: "; cin >> theInput; // Input: -50.5 50 // Q: What is the value of theInput? // A: _____ // -50.5

6. Type string string theInput; cout << "What is your input: "; cin >> theInput; // Input: -50.5 50 // Q: What is the value of theInput? // A: _____ // -50.5

7. Tracing aChar C S 1 4 3 X // Input // CS 143 // X char aChar; int count = 0; cin >> aChar; // Prime read before loop while (aChar != ‘X’) { count ++; cout << aChar; cin >> aChar; } cout << aChar; cout << “Count: “ << count;

8. Function cin.get() The function will read one char at a time Including white spaces!

9. Tracing aChar C S - 1 4 3 \n X // Input // CS 143 // X char aChar; int count = 0; cin.get(aChar); // Prime read before loop while (aChar != ‘X’) { count ++; cout << aChar; cin.get(aChar); } cout << aChar; cout << “Count: “ << count;

10. Function cin.eof() The function returns true or false eof(): end of file end of input From keyboard [CTRL-D] From File Not True after reading the last item in the file True when trying to read after reading the last item in the file

11. Tracing aChar cin.eof() C False S False - False 1 False 4 False 3 False \n False X False ? True // Input // CS 143 // X char aChar; int count = 0; cin.get(aChar); // Prime read before loop while (!cin.eof()) { count ++; cout << aChar; cin.get(aChar); } cout << aChar; cout << “Count: “ << count;

12. int theInput; int count = 0; cout << "What is your input: "; cin >> theInput; while (!cin.eof()) { count ++; cout << "What is your input: "; cin >> theInput; } cout << theInput; cout << “Count: “ << count; // Input: 55 50.5 60 // What is the value of theInput? // Trouble when reading ‘.’!

13. Formatting Output cout << endl << "My output."; cout << "\nMy output."; float average; int count; // Compute count and average cout << endl << count; cout << endl << average; // How many digits displayed for average?

14. #include <iomanip> cout << fixed << showpoint << setprecision(2); // Always display two decimal digits. // No need to remember for quiz/test float value; value = 1 / 3.0; cout << "\nFloat value 1/3.0: " << value; // 0.33 value = 36 / 3.0; cout << "\nFloat value 36/3.0: " << value; // 12.00 value = 1 / 5.0; cout << "\nFloat value 1/5.0: " << value; // 0.20

15. #include <iomanip> cout << fixed << showpoint << setprecision(2); // The setting is applied to all values displayed // until the setting changes. float value; value = 1 / 3.0; cout << "\nFloat value 1/3.0: " << setw(8) << value; // □ □ □ □ 0.33 value = 36 / 3.0; cout << "\nFloat value 36/3.0: " << setw(8) << value; // □ □ □ 12.00 value = 1 / 5.0; cout << "\nFloat value 1/5.0: " << value; // 0.20 (no extra spaces) // setw() is only applied to the next value // It has to be used for every value need the format.

16. Schedule • Prog1 Can still fix style • Prog2: Loops Start Early! Two points Quiz Monday! • Lab 2 Demo by 4pm • Quiz3-4 Due 5 pm Monday • Test 1: Next Friday Note01 – Note10 Prog2:Loops! • Quiz3-5 Now!