Matrix Elements VB-800 Manual do Utilizador descarregar pdf (Página 149)

A6.8 Expressions 141

Table A6.2 OxGauss operator precedence.

Category operators associativity

primary ident ident() constant ()

postﬁx []’.’! left to right

power ^.^ left to right

unary +- right to left

multiplicative .*.*.**~/./ left to right

modulo %

additive +- left to right

horizontal concatenation ~

vertical concatenation |

dot relational .$< .$> .$<= .$>= .$>= .$/=

.< .> .<= .>= .== ./= left to right

dot not .not

dot and .and

dot or .or

dot xor .xor

dot eqv .eqv

relational $< $> $<= $>= $>= $/=

< > <= >= == /= left to right

not not

and and

or or

xor xor

eqv eqv

assignment

∗

the associativity gives the order of the operators.

Subsections below give a more comprehensivediscussion. Several operators require

an lvalue, which is a region of memory to which an assignment can be made. Many

operators require operands of arithmetic type, that is int, double or matrix.

The most common operators are dot-operators (operating element-by-element) and

relational operators (element by element, but returning a single boolean value). The

resulting value is given Tables A6.3 and A6.4 respectively. In addition, there are special

matrix operations, such as matrix multiplication and division; the result from these

operators is explained below. A scalar consists of: int, double or 1 × 1 matrix.

A6.8.1 Primary expressions

An expression in parenthesis is a primary expression. Its main use is to change the

order of evaluation, or clarify the expression. Other forms of primary expressions are:

an identiﬁer, or an identiﬁer preﬁxed by the address operator & (the address can only be

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Matrix Elements VB-800 Manual do Utilizador Página 149