Object oriented programming

java put name before the variable name.

public class test
{
    public static void main(String[] args)
    {
        Picture rocket = new Picture("mariner4.jpg");
        rocket.translate(200, 200);
        rocket.draw();
        Picture planet = new Picture("mars.gif");
        planet.grow(-50, -50);
        planet.draw();
    }
}

public class test
{
    public static void main(String[] args)
    {
        Day birthday = new Day(1951, 5, 26);
        Day lastDay = new Day(2012, 5, 26);
        int daysAlive = lastDay.daysFrom(birthday);
        System.out.println(daysAlive);
    }
}

variable can vary and assignment has no type.

int numberOfPixels = object.methodname(arguments)

public class test
{
    public static void main(String[] args)
    {
        Rectangle box = new Rectangle(60, 90, 20, 30);
        Rectangle box2 = new Rectangle(80, 120, 20, 30);
        box.draw();
        box2.draw();
    }
}

public class test
{
    public static void main(String[] args)
    {
        String river = "Mississippi";
        int numberOfLetters = river.length();
        System.out.println(numberOfLetters);
    }
}

replace method

public class test
{
    public static void main(String[] args)
    {
        String river = "Mississippi";
        String result = river.replaceAll("i","x");
        System.out.println(result);
    }
}

cut space with trim()

String messyString = "Hello, Space!";
        messyString.trim()

AccessorとMutator：「Accessor＝アクセスするヤツ」、「Mutator＝mutate（訳すと変化させる）」
An accessor method is used to return the value of a private field.
A mutator method is used to set a value of a private field. It follows a naming scheme prefixing the word “set” to the start of the method name.

Implement test program, set actual result and expected result.