02-JavaFundamentals

Outprintlnadd new line after this general form a java

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Unformatted text preview: out.print("hello world."); System.out.println(); // print a blank line System.out.println("Add new line after this"); General Form: A Java program // This Java code must be in a file named class-name .java public class class-name { public static void main(String args) { statement(s) } } // Example Program stored in the file HelloWorld.java import java.util.Scanner; public class HelloWorld { public static void main(String args) { Scanner keyboard = new Scanner(System. in); System.out.print( "Enter your name: "); String myName = keyboard.next(); // keyboard input System.out.println( "Hi Rick"); System.out.println( "This is " + myName); } } Primitive Numeric Types Type: A set of values with associated operations Java has many types, a few for storing numbers • Stores integers in int variables • Store floating-point numbers in double variables A few operations for numeric types • Assignment Store a new value into a variable • Arithmetic +, -, * (multiplication), / • Methods Math.sqrt(4.0) Math.max(3, -9) See class Math for others Variables to store numbers To declare and give initial value: type identifier = initial-value ; Examples int creditsA = 4; double gradeA = 3.67; String name = "Chris"; int hours = 10; boolean ready = hours >= 8; Assignment We change the values of variables with assignment operations of this general form variable-name = expression; Examples: double x; int j; // Undefined variables // can not be evaluated j = 1; x = j + 0.23; Memory before and after The primitive variables x and j are undefined at first Variable Name Initial Value Assigned Value j ? 1 x ? ? means undefined 1.23 The expression to the right of = must be a value that the variable can store assignment compatible x = "oooooh nooooo, you can't do that"; // <-Error j = x; // <-Error, can't assign a float to an int Assignment double bill; What is value for bill now? _________ bill = 10.00; bill = bill...
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