Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-61 Java Programming Language.

งานนำเสนอเรื่อง: "Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-61 Java Programming Language."— ใบสำเนางานนำเสนอ:

1 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-61 Java Programming Language Chapter 2 : Primitive Data Type and Operation

2 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 2 Introducing Programming with an Example Listing 2.1 Computing the Area of a Circle This program computes the area of the circle.

3 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 3 Trace a Program Execution public class ComputeArea { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * 3.14159; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } no value radius allocate memory for radius animation

4 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 4 Trace a Program Execution public class ComputeArea { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * 3.14159; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } no value radius memory no value area allocate memory for area animation

5 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 5 Trace a Program Execution public class ComputeArea { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * 3.14159; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } 20 radius no value area assign 20 to radius animation

6 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 6 Trace a Program Execution public class ComputeArea { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * 3.14159; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } 20 radius memory 1256.636 area compute area and assign it to variable area animation

7 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 7 Trace a Program Execution public class ComputeArea { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * 3.14159; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } 20 radius memory 1256.636 area print a message to the console animation

8 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 8 Identifiers F identifier คือคำที่มีความหมายในภาษา ซึ่งเป็น ตัวอักษรที่เรียงต่อเนื่องกัน ประกอบด้วย ตัวอักษร (letters), ตัวเลข (digits), ขีดเส้นใต้ (_) และ dollar signs ($). F identifier จะต้องขึ้นต้นด้วยตัวหนังสือ (letter), ขีดเส้น ใต้ (_), หรือ dollar sign ($). ไม่สามารถขึ้นต้นด้วย ตัวอักษรและคำที่เป็น reserved word.  identifier ไม่สามารถเป็น true, false หรือ null.

9 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 9 การประกาศตัวแปร int x; // Declare x to be an // integer variable; double radius; // Declare radius to // be a double variable; char a; // Declare a to be a // character variable;

10 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 10 ประโยคกำหนดค่า (Assignment Statements) x = 1; // Assign 1 to x; radius = 1.0; // Assign 1.0 to radius; a = 'A'; // Assign 'A' to a;

11 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 11 Declaring and Initializing in One Step F int x = 1; F double d = 1.4;

12 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 12 ค่าคงที่ (Constants) รูปแบบ : final datatype CONSTANTNAME = VALUE; คัวอย่าง เช่น final double PI = 3.14159; final int SIZE = 3;

13 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 13 Primitive Data Types

14 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 14 Primitive Data Types char2 15 (0 to 255)16 bit booleantrue/false1 bit Name Range Storage Size

15 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 15 Numeric Operators

16 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 16 Integer Division +, -, *, /, and % 5 / 2 yields an integer 2. 5.0 / 2 yields a double value 2.5 5 % 2 yields 1 (the remainder of the division)

17 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 17 Number Literals Number literal เป็นค่าคงที่ที่กำหนดให้ โปรแกรมโดยตรง ตัวอย่าง เช่น 34, 1,000,000 และ 5.0 ตัวอย่าง เช่น int i = 34; long x = 1000000; double d = 5.0;

18 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 18 Floating-Point Literals Floating-point literals คือค่าคงที่เลขทศนิยม โดยปกติในภาษาจาวาจะกำหนดให้เป็น double type value. ตัวอย่าง เช่น 5.0 ในภาษาจาวาจะเป็น double value, ไม่ใช่ float value. แต่เราสามารถทำเป็น float ได้โดยใส่อักษร f หรือ F, และสามารถทำ เป็น double ได้โดยใส่อักษร d หรือ D. ตัวอย่างเช่น 100.2f หรือ 100.2F สำหรับ float number, และ 100.2d หรือ 100.2D สำหรับ double number.

19 Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-222158-6 19 Arithmetic Expressions is translated to (3+4*x)/5 – 10*(y-5)*(a+b+c)/x + 9*(4/x + (9+x)/y)