CSE110 Lecture 04

Principles of Programming with Java
Primitive Data Types
(202205)

Transcript

1. CSE110 Principles of Programming with Java Lecture 04: Primitive Data Types Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com Office Hours: By appointment
2. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 3 Test Yourselves
3. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 4 Package an application into a JAR
4. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5 Package an application into a JAR Yes, kind of a ZIP file
5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6 Artifact • From the main menu, select File | Project Structure and click Artifacts. • Click. , point to JAR, and select From modules with dependencies. • Select the Main Class field
6. Java
7. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 8 Summary class global variables methods statements instructions local variables
8. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 9 Reserved Words • The Java reserved words: abstract boolean break byte case catch char class const continue default do double else extends false final finally float for goto if implements import instanceof int interface long native new null package private protected public return short static strictfp super switch synchronized this throw throws transient true try void volatile while
9. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 10 Identifiers • Identifiers are the words a programmer uses in a program • An identifier can be made up of letters, digits, the underscore character ( _ ), and the dollar sign • Identifiers cannot begin with a digit 10
10. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 11 Identifiers • Java is case sensitive, Total, total, and TOTAL are different identifiers • By convention, Java programmers use different case styles for different types of identifiers, such as: o title case for class names - Lincoln o upper case for constants – MAXIMUM o lower case the first letter for methods and variables 11
11. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 12 White Space • Spaces, blank lines, and tabs are called white space • White space is used to separate words and symbols in a program • Extra white space is ignored • Programs should be formatted to enhance readability, using consistent indentation
12. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13 Spaces, Identifiers, and Keywords
13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 14 Variable Declaration (public)(static)type identifier (= value);
14. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 15 Variable Declaration • Multiple variables can be created in one declaration int count, temp, result; • A variable can be given an initial value in the declaration int sum = 0; int base = 32, max = 149;
15. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 16 Using Variables • An assignment statement changes the value of a variable total = 55;
16. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 17 Example
17. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 18 Variable Declaration (public)(static)type identifier (= value);
18. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 19 Data Types § There are exactly eight primitive data types in Java § Four of them represent integers: byte, short, int, long § Two of them represent floating point numbers: float, double § One of them represents characters: char § And one of them represents boolean values: boolean
19. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 20 Data Types The difference between the various numeric primitive types is their size, and therefore the values they can store: Type Size Min Value Max Value byte 8 bits -128 127 short 16 bits -32,768 32,767 int 32 bits -2^31 2^31 - 1 long 64 bits -2^63 2^63 - 1 float 32 bits +/- 3.4 x 1038 with 7 significant digits double 64 bits +/- 1.7 x 10308 with 15 significant digits
20. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 21 char • A char variable stores a single character from the Unicode character set • The Unicode character set uses 16 bits per character, allowing for 65,536 unique characters • It is an international character set, containing symbols and characters from many world languages • Character literals are delimited by single quotes: 'a' 'X' '7' '$' ',' '\n'
21. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 22 Escape Sequences Escape Sequence Meaning \b backspace \t tab \n newline \” double quote \’ single quote \\ backslash
22. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 23 boolean • A boolean value – only 2 values, true or false • The reserved words true and false are the only valid values for a boolean type boolean done = false; boolean success; success = true;
23. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 24 Global Variable
24. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 25 Error
25. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 26 Homework Read Chapter 2 Copy, Compile, and Run all source code in this week slides
26. CSE110 - Principles of Programming Javier Gonzalez-Sanchez javiergs@asu.edu Summer 2022 Disclaimer. These slides can only be used as study material for the class CSE110 at ASU. They cannot be distributed or used for another purpose.