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Final 1

This document discusses Java programming concepts such as identifiers, variables, assignment statements, named constants, numeric data types, reading input from the console, and evaluating expressions. It provides examples of Java code that demonstrate these concepts, such as how to declare variables and constants, perform input/output, and arithmetic operations. Listings of complete Java programs are included to illustrate applying these programming elements. Exercises at the end review the key topics covered.

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Inzamamul Haque
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45 views25 pages

Final 1

This document discusses Java programming concepts such as identifiers, variables, assignment statements, named constants, numeric data types, reading input from the console, and evaluating expressions. It provides examples of Java code that demonstrate these concepts, such as how to declare variables and constants, perform input/output, and arithmetic operations. Listings of complete Java programs are included to illustrate applying these programming elements. Exercises at the end review the key topics covered.

Uploaded by

Inzamamul Haque
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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CHAPTER 02

Sadika Islam Sneha


TO READ : CHAPTER 01
▪ Listing – 1.4, 1.5, 1.6,
▪ Exercise: 1.5, 1.6, 1.8, 1.9, 1.10, 1.12
ELEMENTARY PROGRAMMING
IDENTIFIERS
▪ Identifiers are the names that identify the elements such as classes, methods, and variables in a program.

▪ As you see in Listing 2.3, ComputeAverage, main, input, number1, number2, number3
VARIABLES
▪ Variables are used to represent values that may be changed in the program
ASSIGNMENT STATEMENTS AND ASSIGNMENT
EXPRESSIONS
▪ An assignment statement designates a value for a variable. An assignment statement
can be used as an expression in Java.
NAMED CONSTANTS
▪ A named constant is an identifier that represents a permanent value
▪ Here is the syntax for declaring a constant:
final datatype CONSTANTNAME = value;
▪ The word final is a Java keyword for declaring a constant
▪ Listing 2.4 ComputeAreaWithConstant.java
NAMING CONVENTIONS
▪ Sticking with the Java naming conventions makes your programs easy to read and avoids errors
NUMERIC DATA TYPES AND
OPERATIONS
READING INPUT FROM THE CONSOLE
▪ Reading input from the console enables the program to accept input from the user
▪ Scanner input = new Scanner(System.in);
▪ System.in to the standard input device
▪ To perform console input, you need to use the Scanner class to create an object to read input from System.in
▪ The syntax new Scanner(System.in) creates an object of the Scanner type
▪ The syntax Scanner input declares that input is a variable whose type is Scanner
▪ The whole line Scanner input = new Scanner(System.in) creates a Scanner object and assigns its reference
to the variable input
▪ You can invoke the nextDouble() method to read a double value as follows:
▪ double radius = input.nextDouble();
▪ Listing 2.2 : ComputeAreaWithConsoleInput.java
▪ Listing 2.3: ComputeAverage.java
READING NUMBERS FROM THE
KEYBOARD
Listing 2.5 DisplayTime.java
EXPONENT OPERATIONS
▪ The Math.pow(a, b) method can be used to compute ab. The pow method is defined in the
Math class in the Java API (Application Program Inteface - collection of prewritten packages, classes, and
interfaces with their respective methods, fields and constructors.)
CHECK POINT
EVALUATING EXPRESSIONS AND
OPERATOR PRECEDENCE
CASE STUDY: DISPLAYING THE
CURRENT TIME
▪ You can invoke System.currentTimeMillis() to return the current time.
▪ Do It By Yourself
AUGMENTED ASSIGNMENT
OPERATORS
INCREMENT AND DECREMENT
OPERATORS
NUMERIC TYPE CONVERSIONS
▪ Floating-point numbers can be converted into integers using explicit casting
▪ The following statement
▪ System.out.println((int)1.7);
displays 1. When a double value is cast into an int value, the fractional part is truncated
▪ The following statement
▪ System.out.println((double)1 / 2);
displays 0.5, because 1 is cast to 1.0 first, then 1.0 is divided by 2

Listing 2.8 SalesTax.java


SELF STUDY
▪ 2.16 Software Development Process
▪ 2.17 Case Study: Counting Monetary Units

Exercise of Chapter 02:


▪ 1,2,3,4,5,6,7,9,12,14,15,16,19,20,21,23

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