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Revised: Mon Mar 28 14:22:16 CDT 2016
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Java programs are composed of statements, and statements are constructed from expressions. This module takes a very brief look at Java statements andexpressions.
The first step
The first step in learning to use a new programming language is usually to learn the foundation concepts such as variables, types, expressions,flow-of-control, etc. This module concentrates on expressions and statements.
The hierarchy
Java programs are composed of statements, and statements are constructed from expressions.
An expression is a specific combination of operators and operands, that evaluates to a single value. The operands can be variables, constants, or methodcalls.
A method call evaluates to the value returned by the method.
Named constants
Java supports named constants that are implemented through the use of the final keyword.
The syntax for creating a named constant in Java is as follows:
final float PI = 3.14159; While this is not a constant type, it does produce a value that can be referenced in the program and which cannot be modified.
The final keyword prevents the value of PI from being modified in this case . You will learn later that there are some other uses for the final keyword in Java as well.
Operator precedence
The order in which the operations are performed determines the result. You can control the order of evaluation by the use of matchingparentheses.
If you don't provide such parentheses, the order will be determined by the precedence of the operators (you should find and review a table of Java operator precedence) with the operations having higher precedence being evaluated first.
According to The Java Tutorials , "A statement forms a complete unit of execution."
A statement is constructed by combining one or more expressions into a compound expression and terminating that expression with a semicolon.
As of November 2012, a good tutorial on this topic is available on the Oracle website titled Expressions, Statements, and Blocks .
This section contains a variety of miscellaneous information.
Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.
I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.
In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.
Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.
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