slice_array Class

 

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An internal, auxiliary template class that supports slice objects by providing operations between subset arrays defined by the slice of a valarray.

template <class Type>  
class slice_array : public slice {  
public:  
    typedef Type value_type;  
    void operator=(const valarray<Type>& x) const;

 
    void operator=(const Type& x) const;

 
    void operator*=(const valarray<Type>& x) const;

 
    void operator/=(const valarray<Type>& x) const;

 
    void operator%=(const valarray<Type>& x) const;

 
    void operator+=(const valarray<Type>& x) const;

 
    void operator-=(const valarray<Type>& x) const;

 
    void operator^=(const valarray<Type>& x) const;

 
    void operator&=(const valarray<Type>& x) const;

 
    void operator|=(const valarray<Type>& x) const;

 
    void operator<<=(const valarray<Type>& x) const;

 
    void operator>>=(const valarray<Type>& x) const;

 
// The rest is private or implementation defined  
}  

The class describes an object that stores a reference to an object of class valarray<Type>, along with an object of class slice, which describes the sequence of elements to select from the valarray<Type> object.

The template class is created indirectly by certain valarray operations and cannot be used directly in the program. An internal, auxiliary template class that is used by the slice subscript operator:

slice_array< Type> valarray< Type:: operator[] ( slice).

You construct a slice_array<Type> object only by writing an expression of the form va[sl], for a slice sl of valarray va. The member functions of class slice_array then behave like the corresponding function signatures defined for valarray<Type>, except that only the sequence of selected elements is affected. The sequence controlled by the slice_array is defined by the three parameters of the slice constructor, the index of the first element in the slice, the number of elements, and the distance between the elements. A slice_array cut from valarray va declared by va[ slice(2, 5, 3)] selects elements with indices 2, 5, 8, 11, and 14 from va. The indices must be valid for the procedure to be valid.

See the example for slice::slice for an example of how to declare and use a slice_array.

Header: <valarray>

Namespace: std

Thread Safety in the C++ Standard Library

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