My JAVA programs

For Self Reference purpose,

This repository is to contain my java programs as I learn this language forward.

Basics

Create a file with .java extension Open the file, the main class name is the same name as file.

If the file name is farhan.java then the main class is farhan

// main class
class farhan {
  // code
}

In the main class, the main method is defined as public static void main(String[] args)

The type for main method is always void. args is string array holding all command-line arguments.

Two type of methods exist in Java

1. public
2. private

public methods can be accessed through class instances (Objects) private methods cannot be accessed through class instances

private methods are useful when developers would like to execute a certain code within the class and don't want it to be accessed outside the class through class instances manually.

Rest of the syntax is a similar to that of C language.

Print Hello World Program

// main class
class farhan {
  // main method of main class
  public static void main(String args[])
  {
    System.out.println("Hello World!");
    // 'println' mean print line - prints an additional '\n' at the end | there is also the method 'print' - prints whatever is given without additional '\n' like in 'println'
  }
}

To create a class object, say you created a class calculator with four public methods (sum, dif, product, div) you first create a variable of the class type and then create a class instance with new keyword. It would look like this... calculator calc_object = new calculator();

Here calculator is used as datatype for object calc_object