Class 10: Numeric Values in Java

Held: Monday, 12 September 2005

Summary: Today we begin to explore some issues pertaining to numeric values in Java.

Related Pages:

• EBoard.
• Lab on Numeric Values.
• Reading on Numeric Values.

Notes:

• Are there questions on Homework 1?
• No reading for tomorrow!

Overview:

• Number basics.
• Lab.

Basics of Numbers

• Java provides a wide range of numeric types.
  • You can classify numeric types as to what set of numbers they try to represent (integers vs. reals)
  • You can classify numeric types as to whether they are objects or so-called primitive types.
  • You can classify numeric types as to whether they provide a fixed set of values or whether they permit a nearly arbitrary set of values.
• Here are some of the key numeric types:
  • int : primitive representation of integers with fixed range
  • long : primitive representation of integers with fixed range ; probably the best default for integers
  • short : primitive representation of integers with fixed range
  • double : primitive approximation of real numbers with fixed accuracy ; probably the best default for reals
  • float : primitive approximation of real numbers with fixed accuracy
  • Integer : object representation of integers with fixed range
  • Long : object representation of integers with fixed range
  • Short : object representation of integers with fixed range
  • Double : object approximation of real numbers with fixed accuracy
  • Float : object approximation of real numbers with fixed accuracy
  • BigDecimal : object approximation of real numbers with programmer-specifiable accuracy
  • BigInteger : object representation of integers with arbitrary range
• Note that the fixed accuracy for real numbers depends, in part, on the size of the real number represented.

Lab on Numeric Values

• Questions on the reading?
• Do the lab.
• Be prepared to reflect.