Java Reference
In-Depth Information
• WHAT YOU LEARNED IN THIS CHAPTER
TOPIC
CONCEPT
Relational
Operators
You can use relational operators to compare values, and such comparisons result in values of either
true
or
false
. The relational operators are:
> >= == != <= <
Logical
Operators
You can combine basic comparisons and logical variables in more complex logical expressions by using
logical operators. The logical operators are:
& && | || ^ !
The
if
Statement
The
if
statement is a basic decision-making tool in Java. It enables you to choose to execute a block of
statements if a given logical expression has the value
true
. You can optionally execute another block of
statements if the logical expression is
false
by using the
else
keyword.
The Condi-
tional
Operator
You can use the conditional operator to choose between two expressions depending on the value of a logic-
al expression.
The
switch
Statement
You can use the
switch
statement to choose from a fixed number of alternatives.
Variable
Scope
The variables in a method come into existence at the point at which you declare them and cease to exist
after the end of the block that immediately encloses their declaration. The program extent where the vari-
able is accessible is the scope of the variable.
Loops
You have four ways of repeating a block of statements: a numerical
for
loop, a collection-based
for
loop,
a
while
loop, or a
do-while
loop.
The
continue
statement enables you to skip to the next iteration in the loop containing the
continue
statement. The labeled
continue
statement enables you to skip to the next iteration in an outer loop en-
closing the labeled
continue
that is identified by the label. The labeled loop need not be the loop immedi-
ately enclosing the labeled
continue
.
continue
Statements
The
break
statement enables you to break out of a loop or switch statement. The labeled
break
statement
enables you to break out of a loop or a switch and continue execution at the point in the code identified by
the label. This is not necessarily the block that encloses it directly.
Assertions You use an assertion statement to verify logical conditions that should always be
true
, or as code in parts
of a program that should not be reached, but theoretically can be.
break
Statements
