A class House is the concept of house. It's not a house itself, but it tells us what's common between all houses. In this case, each house has windows (integer), people (integer), and a name. In Java, a class is defined like <protection> class <name> { //code }. You'll end up using public protection level in most cases.
An object House is what you get when you use the constructor of the class House. The object House is a specific House, and thus you can define the amount of windows, amount of people and the name this particular House has. From the example below, you can create a House with the statement House h = new House(x, y, name); where you replace x, y, and name with the actual values you want. Now, h is a House, and you can poke it with methods.
A method is... well, it's pretty much the same as a function. They usually apply to just one House object - let's use h, the House we created. Method definitions are in the form <protection> <returntype> <methodname>(<parameters>) { //code } and calls are in the form <instance>.<methodname>(<parameters, if any>). Using the methods from the example above, you would query the amount of windows from h with the statement h.getWindows(); - because the return type is int (meaning integer), you can assign the returned value to an integer variable: int windows = h.getWindows(); would result in the variable 'windows' containing the amount of windows in the House h.
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But on the other hand, that's already more theory than you need to get started with Java. A lot more. Start working on something small, like Fibonacci numbers or a simple calculator, just ignore the OOP stuff and write it in a single class like you do with most Hello World programs, so you'll get a touch on writing Java code. Since you'll want to read user inputs eventually, I'll give you a short bit that should help you...
Scanner input = new Scanner(System.in); //input is a Scanner - it allows you to read console inputs
String s = input.nextLine(); //Assigns the next text line typed by the user to the variable s
int number = input.nextInt(); //Assigns the next integer typed by the user to the variable number
double floatingPoint = input.nextDouble(); //Assigns the next double-precision floating point number (usually this means real numbers) to the variable floatingPoint
Example on using inputs:
public class HelloName {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Hello, what's your name?");
String name = input.nextLine();
System.out.println("Hello, " + name + "!");
System.out.println("How old are you?");
int age = input.nextInt();
if(age < 18) {
System.out.println("You're a minor in most countries.");
}
else {
System.out.println("You're no longer a minor in most countries.");
}
}
}
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Topic: Java tutorials? (Read 1162 times)