Chapter 2 Helper Sheet

Scanner object knows: How to read from the screen

Package to import: import java.util.Scanner;

How to create a Scanner for your screen:

• Scanner xxx = new Scanner(System.in);

How to use a Scanner to read from your screen:

• int value1 = keyb.nextInt();

Methods that work on Scanner:

• nextInt()
• nextLong()
• nextByte()
• nextDouble()
• next() – up to next whitespace (delimiter)
• nextLine() – up to “\n”
• useDelimiter()
  

NumberFormatter object knows: How to print money

Package to import: import java.text.NumberFormat;

How to create a NumberFormatter for your money:

• NumberFormat moneyFormatter = NumberFormat.getCurrencyInstance();

How to use a NumberFormatter to print to your screen:

• System.out.println(“I bought it for ” + moneyFormatter.format(cost))

DecimalFormatter object knows: How to print decimals

Package to import: import java.text.DecimalFormat;

How to create a DecimalFormatter for your numbers:

• DecimalFormat percentage2 = new DecimalFormat(“0.00%”);

How to use a DecimalFormatter to print to your screen:

• System.out.println(percentage2.format(.308)); // will print 30.80%
  

Different format options:

• 0 = required position
• # = show it if you have it
• % = make it a % (mult by 100)
• E = E notation (scientific)

printf command:

Just like println, but uses variables inside string start % and end character.

%, then size of whole number, then decimal places and then type

• d = int
• f = float
• s = string
• c = char