harvard cs50 intro to computer science

... surprised to learn that computer science is not the study of computers A famous computerscientist named Edsgar Dijkstra once quipped that computers are to computer science what telescopes are toastronomy ... turned a couple computer programming classes into a lucrative career option Computers are so commonplace in thebusiness world today that the ability to understand and program computers might ... of computerscience and is, therefore, important to anyone interested in becoming a computer professional But others canalso benefit from the experience Computers have become a commonplace tool

Ngày tải lên: 25/03/2017, 17:07

... a variable referring to the receiver of the message Trang 22   this – Chaining Constructors • “this” can be used to simplify constructor code by allowing one constructor to call another • We ... variables of the class type • To create instances of the class using constructors • To send messages to instances of the class by invoking class instance methods • To know the class public interface ...  Chapter 7 Classes and Methods III: Static Methods and Variables Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang

Ngày tải lên: 11/01/2020, 18:40

... Java // code to read and display GIF image from file import java.awt.*; Import CSLib.*; … DrawingBox g = new DrawingBox(); … Toolkit tools = Toolkit.getDefaultToolkit(): Image mouse = tools.getImage(“C:/KMR/images/mouse.gif”); ... Trang 1   Chapter 6 Iteration Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... –1 to terminate”); // read first score score = in.readInt(); while ( score != -1 ) { i++; // insert code to process score // read next score score = in.readInt(); } Trang 14   Reading to

Ngày tải lên: 11/01/2020, 18:43

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2   Chapter Preview In this chapter we will: • show how to organize ... provided to programmers along with the Java compiler (e.g Math or MouseEvent) – Java expects to find these classes in separate directories or folders • The classes stored in each directory form ... toString() { String result = toString(); return (result + “:” + second); } • To make a call toString in the superclass instead public void toString() { String result = super.toString(); return (result

Ngày tải lên: 11/01/2020, 18:45

... 1Chapter 14Recursion Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by Trang 2Chapter PreviewIn this chapter we will: • introduce recursion as a programming ... method would be added to IntList public int length() { Trang 28Converting List to String• This method would be added to IntList public String toString() { String myValue = Integer.toString(value); ... would be added to IntList public IntList nth(int n) { Trang 30Adding Element to End of List• This method would be added to IntList public void addToEndM(int n) { Trang 32Adding Element to List in

Ngày tải lên: 11/01/2020, 18:46

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2Chapter Preview In this chapter we will: introduce event ... show how a program can respond to mouse events (e.g clicks and mouse movements) demonstrate how to implement a listener Interface show how mouse events can be used to build highly interactive ... the event Listener classes send messages to an event manager requesting to be notified when a particular message occurs Event managers send messages to listeners notifying them when a particular

Ngày tải lên: 11/01/2020, 18:47

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2   Chapter Preview In this chapter we will: • formally introduce ... initialized to default values if no initializers are found – integers and doubles are initialized to 0 – characters are initialized to the null character (ASCII code 0) – booleans are initialized to ... Reads and stores the hour and minute data String toString() Returns string version of time suitable for printing void setHour(int h) Sets hour to h void setMinute(int m) Sets minute to m int

Ngày tải lên: 11/01/2020, 19:00

... public class TwoButtons extends Frame { Button redButton, blueButton; public TwoButttons() { super(“Two Buttons Frame”); redButton = new Button(“Red” ); blueButton = new Button(“Blue”); Trang ... possible to use inheritance to allow TwoButtons to become a frame tn Its own right ¢ Note that the UML diagram will show TwoButtons as a subclass of Frame ¢ You will need to use super ( )to set ... Trang 4Can use pack( ) to set size to accommodate preferred sizes of components) Trang 5f = new Frame(“Two Buttons Frame”); redButton = new Button(“Red” ); blueButton = new Button(“Blue”); Trang

Ngày tải lên: 11/01/2020, 19:02

... Trang 1   Chapter 2 Classes and Methods I Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) byS.N Kamin, D Mickunas, E Reingold Trang ... source listings to make things more readable • comments – lines beginning with two slashes // – single or multiple lines enclosed by /* */ – that allow the programmer to insert notes to help other ... predefined collections of programs providing services to many programmers (e.g CSLib.* package used throughout the text) • class heading – needs to be included at the beginning of every program –

Ngày tải lên: 11/01/2020, 19:06

... your application will need • If you guess too low, you will still run out of space • You do not need to use all the elements in an array (but total computer memory is finite) Trang 16   Trang ... counts[10] // error – trying to access // variable outside counts Trang 7   Expressions as Subscripts • Array subscripts do not have to be constants • Array subscripts do need to be integer expressions ...  Chapter Preview In this chapter we will: • introduce the array as a structure for storing large amounts of data • discuss common array operations • introduce algorithms for searching and sorting

Ngày tải lên: 11/01/2020, 19:27

... Trang 1Chapter 1 What is Programming? Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... Is pervasive — easy to create multiple objects of the same type — easy to create similar objects without having to rewrite the overlapping code ¢ OOP makes programs easier to understand and more ... 128; 0; 05 +0 Trang 20Running Your Own Java Use an interpreter to execute the compiled program (e.g Java) Return to the editor to correct any errors (or bugs) and start the cycle again Trang

Ngày tải lên: 11/01/2020, 19:29

... Trang 1   Chapter 3 Fundamental Data Types of Java Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) byS.N Kamin, D Mickunas, E Reingold Trang ... int is not infinitely large and it is possible to compute a value incorrectly because the value is too large to be stored in an int variable storage location • Unlike the real numbers in mathematics ... is legal to assign a n int to an char variable char c = 97; // assigns ‘a’ to c • It is possible to perform arithmetic on char variables char ch = ‘a’; ch = ch + 1; // assigns ‘b’ to ch

Ngày tải lên: 11/01/2020, 20:03

... Row Totals double [] yearTotals = new double[ROWS]; for (y = 0; y < ROWS; y++) { // compute total for year y yearTotals[y] = 0.0; for (s =0; s < COLS; s++) yearTotals[y] = yearTotals[y] ... Trang 1   Chapter 9 Nested Loops and Two-Dimensional Arrays Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... double[COLS]; Trang 15   Computer Graphics • Computer graphics is the study of methods of representing and manipulating images • A two-dimensional array can be used to represent the image to be displayed

Ngày tải lên: 11/01/2020, 20:21

... Trang 1Chapter 15Text Processing and File Input/Output Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... Java provides constructors for each class • The StringBuffer class also contains a ToString method to allow easier output Trang 5Sequential Files• Files are stored are stored on disks • In this ... end of line • PrintWriter is a wrapper class provided to convert several data type values to printable forms Trang 14Writing to a File• To make a file available for printing PrintWriter pr =

Ngày tải lên: 11/01/2020, 20:25

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2Chapter PreviewIn this chapter we will: • introduce class ... it as a message to an object • The class method f in the class C is invoked using the notation f.C( … ) • It has no receiver and cannot refer to instance variables • It can refer to and manipulate ... variable, not one instance per object • Created by adding the modifier static to the variables declaration • Allows variables to be modified once for all class objects • Can be accessed by class methods

Ngày tải lên: 11/01/2020, 20:29

... Trang 1   Chapter 4 Decision Making Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... selector variables in Java switch statements Trang 4   Trang 5   Relational Operators < < less than > > greater than <= less than or equal to >= greater than or equal to = ... at 9:00 today”); out.println(“Math meets at 10:00 today”); break; case TUESDAY: case THURSDAY: out.println(“English meets at 9:00 today”); out.println(“Chemistry meets at 10:00 today”);

Ngày tải lên: 11/01/2020, 20:31

... a variable referring to the receiver of the message Trang 22   this – Chaining Constructors • “this” can be used to simplify constructor code by allowing one constructor to call another • We ... variables of the class type • To create instances of the class using constructors • To send messages to instances of the class by invoking class instance methods • To know the class public interface ...  Chapter 7 Classes and Methods III: Static Methods and Variables Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang

Ngày tải lên: 15/05/2020, 22:27

... Row Totals double [] yearTotals = new double[ROWS]; for (y = 0; y < ROWS; y++) { // compute total for year y yearTotals[y] = 0.0; for (s =0; s < COLS; s++) yearTotals[y] = yearTotals[y] ... Trang 1   Chapter 9 Nested Loops and Two-Dimensional Arrays Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang ... double[COLS]; Trang 15   Computer Graphics • Computer graphics is the study of methods of representing and manipulating images • A two-dimensional array can be used to represent the image to be displayed

Ngày tải lên: 15/05/2020, 22:29

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2   Chapter Preview In this chapter we will: • show how to organize ... provided to programmers along with the Java compiler (e.g Math or MouseEvent) – Java expects to find these classes in separate directories or folders • The classes stored in each directory form ... toString() { String result = toString(); return (result + “:” + second); } • To make a call toString in the superclass instead public void toString() { String result = super.toString(); return (result

Ngày tải lên: 15/05/2020, 22:33

... Lecture Slides to Accompany An Introduction to Computer Science Using Java (2nd Edition) by S.N Kamin, D Mickunas, E Reingold Trang 2Chapter PreviewIn this chapter we will: • introduce class ... it as a message to an object • The class method f in the class C is invoked using the notation f.C( … ) • It has no receiver and cannot refer to instance variables • It can refer to and manipulate ... variable, not one instance per object • Created by adding the modifier static to the variables declaration • Allows variables to be modified once for all class objects • Can be accessed by class methods

Ngày tải lên: 15/05/2020, 22:34