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Since the Java expression language is not very rich, Java programs express computations as sequences of statements rather than as compound expressions. The most common form of Java statement is an assignment statement type var = expr ; where type is a Java type name, var is a Java variable name, and expr is an expression of type compatible with the type of var. The assignment statement int x = 5; asserts that ``the variable x has value 5''.
int x = 5; x*x double d = .000001; double dd = d*d; dd dd*dd 1. + dd 1. + dd*dd Did you get the answers that you expected? Java variable names and type names must be identifiers. An identifier is any sequence of ``alphanumeric characters'' (letters, digits, and _) beginning with a letter or _--except for the following keywords, which are reserved and may not be used as variable names or type names: abstract default if private throw boolean do implements protected throws break double import public transient byte else instanceof return try case extends int short void catch final interface static volatile char finally long super while class float native switch const for new synchronized continue goto package this Java is case-sensitive; the variable X is distinct from the variable x. There are three kinds of variables in Java: fields, method parameters, and local variables. See the section on declaring variables. Java includes all of the basic statement forms found in the C programming language expressed in essentially the same syntax. Although Java accepts most C syntax, many common C constructions are considered bad style in Java.
(Written by Corky Cartwright. Modified by Stephen Wong) |