The Department of Computer Science & Engineering 
STUART C. SHAPIRO: CSE
115 C

If you have set of basic operations/actions/behaviors, how can you combine them to make a more complex operation/action/behavior?
According to a theorem proved by Corrado Böhm and Giuseppe Jacopini (CACM, 1966), all you need is:
A block is a sequence of statements surrounded by braces (curly
brackets), { ... }
.
Anywhere a statement is legal, a block may be used.
if (condition) statement_{1}
else statement_{2}
]statement
could be a block.)
condition
is a Java expression that evaluates to a
boolean value (true
or false
).
If the condition
evaluates to
true
, statement_{1}
is
executed.
If the condition
evaluates to
false
, statement_{1}
is not
executed, and if the else
clause is present, statement_{2}
is executed.
A conditional expression in Java is
(condition ? expression_{1} : expression_{2})
The parentheses are optional.
If the condition
evaluates to
true
, the conditional expression evaluates to the value
of expression_{1}
.
If the condition
evaluates to
false
, the conditional expression evaluates to the value
of expression_{2}
.
boolean
is a Java primitive (base) type like
int
and double
.
It has only two values, true
and false
.
boolean operators:
not:
p  !p 

true  false 
false  true 
and, or, exclusive or, equivalent, not equivalent:
p  q  p && q  p  q  p ^ q  p == q  p != q 

true  true  true  true  false  true  false 
true  false  false  true  true  false  true 
false  true  false  true  true  false  true 
false  false  false  false  false  true  false 
Relational operators:
Operate on two numbers, evaluates to a boolean.
==  equal to 
!=  not equal to 
<  less than 
>  greater than 
<=  less than or equal to 
>=  greater than or equal to 
See Example code.