Java Crash Course: Calling functions смотреть онлайн

Java: Calling Functions

Follow along with the instructions at: https://fullstackclouddeveloper.com/course/java-for-beginners/index.html#calling_functions

Java class functions and methods define blocks of code that may receive inputs as parameters and may return an output. A function and a method are both declared with the function keyword. The only difference being a naming convention where functions return a value and methods do not.

Calling functions in this class

To call a function in this class, simply call it by function name or you can use the this keyword

String message = getMessage(name);

Or

String message = this.getMessage(name);

Calling functions in another class

To call a function in an instance of another class use the instance variable followed by a . then the function name

Another other = new Another();
String message = other.getMessage(name);

Exercise 2: Calling functions

Create a new class named Greeting with a function named hello that returns a String "Hello, World!"

public class Greeting {
public String hello() {
return "Hello, World!";
}
}

Modify our HelloWorld.java application we created in the Hello, World! lesson to call the Greeting class to say hello instead of the String literal "Hello, World!" Don't forget to use the new keyword to create a new instance of Greeting.

Here is the HelloWorld.java application again in case you need to recreate it.

HelloWorld.java

public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}

NOTE: One of the things I have noticed about VS Code is it is compiling our Java classes for us so they are ready to run once they are compilable.