Lecture Notes on 07 Sep 2011

Steps in Learning a Computer Language

* Write the Hello World program

* Characterset -ASCII & Unicode 

* Variables 

* Types - short, int long, float, double, char, boolean, byte

* Operators
    - Arithmetic: + - * / %
    - Comparison: > >= < <= == !=
    - Boolean: ! && || ^

* Statements

* Conditionals

* Loops

* Methods

* Arrays

* Input / Output

* Class

// Program to compute the area of a circle

import java.util.Scanner;

public class Test
{
  public static void main (String[] args)
  {
    // Create a Scanner object
    Scanner sc = new Scanner (System.in);

    // Prompt the user to enter the radius
    System.out.print ("Enter radius: ");

    // Read the user input
    double radius = sc.nextDouble();

    // Compute the area
    double area = Math.PI * radius * radius;

    // Write out the result
    System.out.println ("Area = " + area);
  }
}