Java Reference
In-Depth Information
a smaller set of values to a type with a wider set of values.
• Byteintegertoshortinteger,integer,longinteger,floating-point,ordoublepre-
cision floating-point
• Short integer to integer, long integer, floating-point, or double precision
• Character to integer, long integer, floating-point, or double precision floating-
• Integer to long integer, floating-point, or double precision floating-point
• Long integer to floating-point or double precision floating-point
• Floating-point to double precision floating-point
Note When converting from a smaller integer to a larger integer, Java copies the
smaller integer's sign bit into the extra bits of the larger integer.
Chapter2 discussesthewideningconversionrulesforperformingtypeconversionsin
the context of user-defined and array types.
Compound Expressions
A compound expression isasequenceofsimpleexpressionsandoperators,wherean op-
erator (asequenceofinstructionssymbolicallyrepresentedinsourcecode)transforms
its operand expressionvalue(s)intoanothervalue.Forexample, -6 isacompoundex-
pression consisting of operator - and integer literal 6 as its operand. This expression
transforms 6 intoitsnegativeequivalent.Similarly, x+5 isacompoundexpressioncon-
sisting ofvariable name x ,integer literal 5 ,andoperator + sandwiched between these
operands. Variable x 's value is fetched and added to 5 when this expression is evalu-
ated. The sum becomes the value of the expression.
Note If x 's type is byte integer or short integer, this variable's value is widened
to an integer. However, if x 's type is long integer, floating-point, or double precision
floating-point, 5 is widened to the appropriate type. The addition operation is per-
formed after the widening conversion takes place.
theytake.A unary operator takesonlyoneoperand(unaryminus[ - ]isanexample),a
binary operator takestwooperands(addition[ + ]isanexample),andJava'ssingle tern-
ary operator (conditional [ ?: ]) takes three operands.
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