slice_array(3C++) - slice_array(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEslice_array
- A numeric array class for representing a BLAS-like slice from a
valarray.
SYNOPSIS
#include <valarray>
template <class T>
class slice_array ;
DESCRIPTION
slice_array<T> gives a slice view into a valarray. Slice_arrays are
only produced by applying the slice subscript operator to a valarray.
The elements in a slice_array are references to selected elements in
the valarray (so changing an element in the slice_array really changes
the corresponding element in the valarray). A slice_array does not
itself hold any distinct elements. The template cannot be instantiated
directly since all its constructors are private. However, you can eas‐
ily copy a slice_array to a valarray using either the valarray copy
constructor or the assignment operator. Reference semantics are lost at
that point.
INTERFACE
template <class T> class slice_array {
public:
// types
typedef T value_type;
// destructor
~slice_array();
// public assignment
void operator= (const valarray<T>& array) const;
// computed assignment
void operator*= (const valarray<T>& array) const;
void operator/= (const valarray<T>& array) const;
void operator%= (const valarray<T>& array) const;
void operator+= (const valarray<T>& array) const;
void operator-= (const valarray<T>& array) const;
void operator^= (const valarray<T>& array) const;
void operator&= (const valarray<T>& array) const;
void operator|= (const valarray<T>& array) const;
void operator<<= (const valarray<T>& array) const;
void operator>>= (const valarray<T>& array) const;
// other
void operator= (const T&);
private:
// constructors
slice_array();
slice_array(const slice_array<T>&);
// operator =
slice_array<T>& operator= (const slice_array<T>& array);
};
CONSTRUCTORSslice_array();
slice_array(const slice_array&);
All slice_array constructors are private and cannot be called directly.
This prevents copy construction of slice_arrays.
ASSIGNMENT OPERATORS
void operator=(const valarray<T>& x) const;
Assigns values from x to the selected elements of the valarray that self
refers to. Remember that a slice_array never holds any elements itself, it
simply refers to selected elements in the valarray used to generate it.
slice_array<;T>&
operator=(const slice-_array<T>& x);
Private assignment operator. Cannot be called directly, thus preventing
assignment between slice_arrays.
COMPUTED ASSIGNMENT OPERATORS
void operator*=(const valarray<T>& val) const;
void operator/=(const valarray<T>& val) const;
void operator%=(const valarray<T>& val) const;
void operator+=(const valarray<T>& val) const;
void operator-=(const valarray<T>& val) const;
void operator^=(const valarray<T>& val) const;
void operator&=(const valarray<T>& val) const;
void operator|=(const valarray<T>& val) const;
void operator<<=(const valarray<T>& val) const;
void operator>>=(const valarray<T>& val) const;
Applies the indicated operation using elements from val to the selected
elements of the valarray that self refers to. Remember that a slice_array
never holds any elements itself; it simply refers to selected elements in
the valarray used to generate it.
MEMBER FUNCTIONS
void operator= (const T& x);
Assigns x to the selected elements of the valarray that self refers to.
EXAMPLE
//
// slice_array.cpp
//
#include "valarray.h" // Contains a valarray
// stream inserter
using namespace std;
int main(void)
{
int ibuf[10] = {0,1,2,3,4,5,6,7,8,9};
int ibuf2[5] = {1,3,5,7,9};
// create a valarray of ints
valarray<int> vi(ibuf,10);
valarray<int> vi2(ibuf2,5);
// print it out
cout << vi << endl << vi2 << endl;
// Get a slice and assign that slice to another array
slice_array<int> sl = vi[slice(1,5,2)];
valarray<int> vi3 = sl;
// print out the slice
cout << vi3 << endl;
// Add slice from vi2 to slice of vi1
sl += vi2;
// print out vi1 again
cout << vi << endl;
return 0;
}
Program Output
[0,1,2,3,4,5,6,7,8,9]
[1,3,5,7,9]
[1,3,5,7,9]
[0,2,2,6,4,10,6,14,8,18]
WARNINGS
If your compiler does not support namespaces, then you do not need the
using declaration for std.
SEE ALSO
slice, valarray, gslice, gslice_array, mask_array, indirect_array
Rogue Wave Software 02 Apr 1998 slice_array(3C++)
