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| Category: algorithms | | Component type: function |
Prototype
template <class ForwardIterator, class Generator>
void generate(ForwardIterator first, ForwardIterator last, Generator gen);
Description
Generate assigns the result of invoking gen, a functors that takes no arguments, to each element in the range [first, last). [1]
Definition
Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.
Requirements on types
-
ForwardIterator is a model of ForwardIterator. [2]
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ForwardIterator is mutable.
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Generator is a model of Generator.
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Generator's result type is convertible to ForwardIterator's value type.
Preconditions
-
[first, last) is a valid range.
Complexity
Linear. Exactly last - first invocations of gen. [1]
Example
Fill a vector with random numbers, using the standard C library function rand.
vector<int> V;
...
generate(V.begin(), V.end(), rand);
Notes
[1] The functors gen is invoked for each iterator in the range [first, last), as opposed to just being invoked a single time outside the loop. This distinction is important because a Generator need not return the same result each time it is invoked; it is permitted to read from a file, refer to and modify local state, and so on.
[2] The reason that generate requires its argument to be a mutable ForwardIterator, rather than just an OutputIterator, is that it uses a range [first, last) of iterators. There is no sensible way to describe a range of OutputIterator, because it is impossible to compare two OutputIterator for equality. The generate_n algorithm does have an interface that permits use of an OutputIterator.
See also
copy, fill, fill_n, generate_n, iota
