1. CS 1430: Programming in C++
Turn in your Quiz1-2
No time to cover HiC

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 statement each line
// One or more variables of same
// type each declaration statement
// Style: one space after comma

4. Variables and Memory num1 num2 Sum average 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 \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 together1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c 10 d e f
‘C’: 67
All upper case letters together
All lower case letters are together
All digits 0 through 9 are together
‘Y’: ‘9’: 57

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

12. Input cin >> num1; // cin: standard input stream
// input comes in from the keyboard
// >> : input operator
// Extraction operator
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 goes to the monitor
// << : output operator
// Insertion operator

14. Input Prompt Prompt: Message to tell user what to do.
cin >> num1;
// Program is waiting for input
// User does not know what to do
cout << “Enter the first number: “;
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:
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
<< “numbers is ” << average << “.”;
// The average of the two number is 4.5.
<< “numbers is ” << average << ‘.’;
// 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; // [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; }
Should be in next note!

24. (Go to my home page first) Treat it like a Lab Complete the program
Quiz 1-3
1 point
Due 5 PM, Friday
Download Quiz1-3.cpp
(Go to my home page first)
Treat it like a Lab
Complete the program
(Follow DO instructions)
(Do not delete DO instructions)
Submit to Grader
YangQ-Quiz1-3
Differences: NONE
Lab0 instructions
Should be in next note!

25. Lab1 5 points by Thursday, at 5pm
3 points by the following Tuesday, at 5pm
Zero points after that
Where to find the Lab?
K: drive
Lab Help Session
Thursday, 9 - 3

26. Program 1 Available on Web site and K: drive
Can wait until IF statement is covered
Due Date: 9/21/2015
Grace Date: 9/24/2015

27. Notes On our class home page at
Can print out before class
Should review the notes