43 lines
1.4 KiB
Markdown
43 lines
1.4 KiB
Markdown
[indirect.array.assign]
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# 29 Numerics library [[numerics]](./#numerics)
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## 29.6 Numeric arrays [[numarray]](numarray#indirect.array.assign)
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### 29.6.9 Class template indirect_array [[template.indirect.array]](template.indirect.array#indirect.array.assign)
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#### 29.6.9.2 Assignment [indirect.array.assign]
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[ð](#lib:operator=,indirect_array)
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`void operator=(const valarray<T>&) const;
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const indirect_array& operator=(const indirect_array&) const;
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`
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L9057)
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These assignment operators have reference semantics, assigning the values
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of the argument array elements to selected elements of thevalarray<T> object to which it refers[.](#1.sentence-1)
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L9063)
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If theindirect_array specifies an element in thevalarray<T> object to which it refers more than once, the behavior is undefined[.](#2.sentence-1)
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L9071)
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[*Example [1](#example-1)*:
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int addr[] = {2, 3, 1, 4, 4};
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valarray<size_t> indirect(addr, 5);
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valarray<double> a(0., 10), b(1., 5);
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a[indirect] = b; results in undefined behavior since element 4 is specified twice in the
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indirection[.](#3.sentence-1)
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â *end example*]
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