arrays-usertype.texi

来自「A C++ class library for scientific compu」· TEXI 代码 · 共 43 行

@node Array usertype
@section Creating arrays of a user type
@cindex Array of your own types

You can use the @code{Array} class with types you have created yourself, or
types from another library.  If you want to do arithmetic on the array,
whatever operators you use on the arrays have to be defined on the
underlying type.

For example, here's a simple class for doing fixed point computations in the
interval [0,1]:

@smallexample
@include examples/fixed-point.texi
@end smallexample

The function @code{huge(T)} returns the largest representable value for type
T; in the example above, it's equal to @code{UINT_MAX}.

The @code{FixedPoint} class declares three useful operations: conversion
from @code{double}, addition, and outputing to an @code{ostream}.  We can
use all of these operations on an @code{Array<FixedPoint>} object:

@smallexample
@include examples/fixed.texi
@end smallexample

Note that the array @code{A} is initialized using a comma-delimited list of
@code{double}; this makes use of the constructor @code{FixedPoint(double)}.
The assignment @code{B = A + 0.05} uses
@code{FixedPoint::operator+(FixedPoint)}, with an implicit conversion from
@code{double} to @code{FixedPoint}.  Formatting the array @code{B} onto the
standard output stream is done using the output operator defined for
@code{FixedPoint}.

Here's the program output:

@smallexample
@include examples/fixed.out
@end smallexample