Java Programming Language Chapter 2 Primitive Data Type

Introducing Programming with an Example Listing 2. 1 Computing the Area of a Circle

animation Trace a Program Execution public class Compute. Area { /** Main method */

การประกาศตวแปร int x; // Declare x to be an // integer variable; double radius;

ประโยคกำหนดคา (Assignment Statements) x = 1; // Assign 1 to x; radius = 1.

Declaring and Initializing in One Step F int x = 1; F double d

คาคงท (Constants) รปแบบ : final datatype CONSTANTNAME = VALUE; ควอยาง เชน final double PI

Primitive Data Types Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education,

Primitive Data Types Range Name char boolean Storage Size 215 (0 to 255) true/false

Numeric Operators Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc.

Integer Division +, -, *, /, and % 5 / 2 yields an integer

Number Literals Number literal เปนคาคงททกำหนดใหโปรแกรมโดยตรง ตวอยาง เชน 34, 1, 000 และ 5. 0 ตวอยาง

Arithmetic Expressions is translated to (3+4*x)/5 – 10*(y-5)*(a+b+c)/x + 9*(4/x + (9+x)/y) Liang, Introduction

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Introducing Programming with an Example Listing 2. 1 Computing the Area of a Circle This program computes the area of the circle. Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 2

animation Trace a Program Execution public class Compute. Area { /** Main method */ public static void main(String[] args) { double radius; double area; allocate memory for radius no value // Assign a radius = 20; // Compute area = radius * 3. 14159; // Display results System. out. println("The area for the circle of radius " + radius + " is " + area); } } Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 3

animation Trace a Program Execution public class Compute. Area { /** Main method */ public static void main(String[] args) { double radius; double area; // Assign a radius = 20; // Compute area = radius * 3. 14159; memory radius no value area no value allocate memory for area // Display results System. out. println("The area for the circle of radius " + radius + " is " + area); } } Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 4

animation Trace a Program Execution public class Compute. Area { /** Main method */ public static void main(String[] args) { double radius; double area; assign 20 to radius area 20 no value // Assign a radius = 20; // Compute area = radius * 3. 14159; // Display results System. out. println("The area for the circle of radius " + radius + " is " + area); } } Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 5

animation Trace a Program Execution public class Compute. Area { /** Main method */ public static void main(String[] args) { double radius; double area; memory radius area 20 1256. 636 // Assign a radius = 20; // Compute area = radius * 3. 14159; compute area and assign it to variable area // Display results System. out. println("The area for the circle of radius " + radius + " is " + area); } } Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 6

animation Trace a Program Execution public class Compute. Area { /** Main method */ public static void main(String[] args) { double radius; double area; memory radius area 20 1256. 636 // Assign a radius = 20; // Compute area = radius * 3. 14159; print a message to the console // Display results System. out. println("The area for the circle of radius " + radius + " is " + area); } } Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 7

การประกาศตวแปร 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; Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 9

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

คาคงท (Constants) รปแบบ : final datatype CONSTANTNAME = VALUE; ควอยาง เชน final double PI = 3. 14159; final int SIZE = 3; Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 12

Primitive Data Types Range Name char boolean Storage Size 215 (0 to 255) true/false Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 16 bit 14

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) Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 16

Number Literals Number literal เปนคาคงททกำหนดใหโปรแกรมโดยตรง ตวอยาง เชน 34, 1, 000 และ 5. 0 ตวอยาง เชน int i = 34; long x = 1000000; double d = 5. 0; Liang, Introduction to Java Programming, Sixth Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0 -13 -222158 -6 17

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