CS 1430: Programming in C++

1. CS 1430: Programming in C++ Turn in your Quiz1-2

2. Add Two Numbers Sum = num1 + num2; // Where to store the values? // Must declare Sum, num1, num2

3. Declaration Statements int num1, num2; int Sum; float average; // One or more variables each line // Style: one space after comma

4. Variables and Memory int num1, num2; int Sum; float average; //What values in the memory? // Uninitialized // Garbage! num1 = 4; num2 = 5; Sum = num1 + num2; average = Sum / 2; // What is value of average? // How to get 4.5? average = Sum / 2.0; num1 num2 Sum 4 5 9 average 4.0

5. Identifiers • To identify memory space • Good Identifiers Sum, num1, num2, average total_score, totalScore, TotalScore • Bad Identifiers 1num, 2num total-score, totalscore, Total Score x, y, z, t, s, n, o

6. C++ Data Types int : 2 bytes, range: (-32,768 to 32,767) float: 4 bytes, range (much larger) Storage (and Range) is machine/system dependent Other Numerical Data Types short, long double

7. C++ Data Types (II) // char : 1 byte char theChar = ‘A’; // string: one byte for each char // one more byte at the end to // indicating the end string myString = “CS 143”;

8. C++ Data Types and Storage int num1, num2; int Sum; float average; num1 = 4; num2 = 5; Sum = num1 + num2; average = Sum / 2.0; char grade = ‘A’; string courseName; courseName = “CS143”; num1 num2 Sum 4 5 9 average 4.5 courseName grade C S 1 4 3 \0 A

9. Char and Integer One Byte 01000011 What is the value of the byte? As integer: 67 As ASCII char: ‘C’

10. ASCII Code Table ‘C’: 67 All upper case letters together All lower case letters are together All digits 0 through 9 are together ‘Y’: 89 ‘9’: 57

11. ASCII Code Char ASCII Code ‘C’: 67 ‘D’: ? ‘B’: ? ‘0’: 48 ‘5’: ?

12. Input cin >> num1; // cin: standard input stream // >> : input operator // Extraction operator // input comes in from the keyboard cin >> num1 >> num2; // Style: one space before and after // each operator (>>)

13. Output Sum = num1 + num2; average = Sum / 2.0; cout << average; // cout: standard output stream // << : output operator // Insertion operator // output goes to the monitor

14. Input Prompt Prompt: Message to tell user what to do. cin >> num1; // Prog is waiting for input // User does not know what to do cout << “Enter the first number: “; cin >> num1; cout << “Enter the second number: “; cin >> num2;

15. Input Prompt (II) // Another way to do it: cout << "Enter two numbers: "; cin >> num1 >> num2; // Two numbers separated by spaces/[Enter] // Still another way to do it: cout << "Enter two numbers: "; cin >> num1; cin >> num2;

16. Output Message cout << average; // 4.5 // 4.5 // User does not know what it is cout << “The average of the two ” << “numbers is ” << average; // The average of the two number is 4.5 cout << “The average of the two ” << “numbers is ” << average << “.”; // The average of the two number is 4.5. cout << “The average of the two ” << “numbers is ” << average << ‘.’; // The average of the two number is 4.5. // STYLE: Align the output operators!

17. Using String Variables string prompt = "Enter two integers: "; string message = “The average of the two numbers is “; cout << prompt; // Enter two integers: cin >> num1 >> num2; // 4 5 [ENTER] Sum = num1 + num2; average = Sum / 2.0; cout << message << average << ‘.’; // The average of the two numbers is 4.5.

18. Include File #include <iostream> using namespace std; // standard

19. Organize Output // endl: go to the beginning of next line // ‘\n’: special char, same as endl cout << ‘\n’ << “Enter the first number: ”; cin >> num1; cout << “\n\nEnter the second number: ”; cin >> num2; Sum = num1 + num2; average = Sum / 2.0; cout << endl << endl; cout << “The average of the two ” << “numbers is ” << average << ‘.’ << endl;

20. Organize Output (II) string prompt2 = “\nEnter the second number: ”; string messageAvg = “\n\nThe average of the two numbers is ”; cout << endl << “Enter the first number: ”; cin >> num1; cout << prompt2; cin >> num2; Sum = num1 + num2; average = Sum / 2.0; cout << messageAvg << average << “.” << endl;

21. A Complete Program Semantics Syntax Style

22. //--------------------------------------------------------------//-------------------------------------------------------------- // Name: Qi Yang // // Course: CS143, Section 9, Spring 2011 // // Description: This program computes the float average of two // integers. // // Input: Two integers. // // Output: The float average of the two integers. // //-------------------------------------------------------------- #include <iostream> using namespace std; int main() { float average; int num1, num2; cout << endl << "Enter the first integer: "; cin >> num1; // 3 cout << endl << "Enter the second integer: "; cin >> num2; // 4 average = (num1 + num2) / 2; // Do we get float average? cout << “\nThe average is " << average << ‘.’; return 0; }

23. //--------------------------------------------------------------//-------------------------------------------------------------- // Name: Qi Yang // // Course: CS143, Section 9, Spring 2011 // // Description: This program computes the float average of two // integers // // Input: Two integers // // Output: The float average of the two integers // //-------------------------------------------------------------- #include <iostream> using namespace std; int main() { float average; int num1, num2; cout << endl << "Enter the first integer: "; cin >> num1; // 3 cout << endl << "Enter the second integer: "; cin >> num2; // 4 average = (num1 + num2) / 2.0; cout << “\nThe average is " << average << ‘.’; return 0; }

24. Quiz 1-3 1 point Due 5 PM, Monday • Download Quiz1-3.cpp (Not in D2L) • Open it in HiC • Complete the program (Follow DO instructions) (Do not delete DO instructions) • Submit to HiC server • Differences: NONE • Lab0 instructions

25. Lab0 Submit to HiC Server Differences: NONE Email to YangQ@uwplatt.edu Don’t print out the log file Keep a copy of it

26. HiC Arrange Windows Line number Column number