cs 1430: programming in c++
DESCRIPTION
CS 1430: Programming in C++. Turn in your Quiz1-2. Add Two Numbers. Sum = num1 + num2; // Where to store the values? // Must declare Sum, num1, num2. Declaration Statements. int num1, num2; int Sum; float average; // One or more variables each line // Style: one space after comma. - PowerPoint PPT PresentationTRANSCRIPT
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CS 1430: Programming in C++
Turn in your Quiz1-2
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Add Two Numbers
Sum = num1 + num2;
// Where to store the values?
// Must declare Sum, num1, num2
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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
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Variables and Memory
num1 num2
average
Sumint 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;
4 5 9
4.0
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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
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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
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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”;
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C++ Data Types and Storage
num1 num2
average
Sumint num1, num2;int Sum;float average;
num1 = 4;num2 = 5;
Sum = num1 + num2;average = Sum / 2.0;
char grade = ‘A’;string courseName;
courseName = “CS143”;
4 5 9
4.5
AC S 1 4 3 \0
courseName grade
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Char and Integer
One Byte 01000011
What is the value of the byte?
As integer: 67
As ASCII char: ‘C’
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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
0 1 2 3 4 5 6 7 8 9
4 0 1
5 2 3 4 5 6 7 8 9
6 A B C D E
7 F G H I J K L M N O
8 P Q R S T U V W X Y
9 Z a b c
10 d e f
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ASCII Code
Char ASCII Code
‘C’: 67
‘D’: ?
‘B’: ?
‘0’: 48
‘5’: ?
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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 (>>)
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Output
Sum = num1 + num2; average = Sum / 2.0;
cout << average; // cout: standard output stream // output goes to the monitor// << : output operator // Insertion operator
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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: “; cin >> num1; cout << “Enter the second number: “; cin >> num2;
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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;
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Output Messagecout << 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!
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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.
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Include File
#include <iostream>
using namespace std;
// standard
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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;
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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;
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A Complete Program
Semantics
Syntax
Style
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//--------------------------------------------------------------// 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; }
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//--------------------------------------------------------------// 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; }
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Quiz 1-31 point
Due 5 PM, Friday
1. Download Quiz1-3.cpp (Go to my home page first)2. Treat it like a Lab3. Complete the program (Follow DO instructions) (Do not delete DO instructions)4. Submit to Grader YangQ-Quiz1-35. Differences: NONE6. Lab0 instructions
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 - 325
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
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Notes
• On our class home page at
http://people.uwplatt.edu/~yangq/cs143/
• Can print out before class
• Should review the notes
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