Flow of Control - Absolute Java - page 114

PITFALL: Using = in Place of ==

Because the equal sign, = , is used for assignment in Java, something else is needed to
indicate equality. In Java, equality is indicated with two equal signs with no space
between them, as in

if (yourScore == myScore)
System.out.println("A tie.");
Fortunately, if you do use = in place of == , Java will probably give you a compiler
error message. (The only case that does not give an error message is when the expression
in parentheses happens to form a correct assignment to a boolean variable.) ■

Display 3.3 Java Comparison Operators

MATH NOTATION NAME JAVA NOTATION JAVA EXAMPLES

= == x + 7 == 2*y

answer == 'y'

Equal to

≠ != score != 0

answer != 'y'

Not equal to

> > time > limit

Greater than

≥ >= age >= 21

Greater than or equal to

< < pressure < max

Less than

≤ <= time <=limit

Less than or equal to

The Methods equals and equalsIgnoreCase
When testing strings for equality, do not use == . Instead, use either equals or
equalsIgnoreCase .
SYNTAX
String .equals( Other_String )
String .equalsIgnoreCase( Other_String )
EXAMPLE
String s1;
.
.
.