std::generate
From cppreference.com
Defined in header
<algorithm>
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template< class ForwardIt, class Generator >
void generate( ForwardIt first, ForwardIt last, Generator g ); |
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Assigns each element in range [first, last)
a value generated by the given function object g
.
Contents |
[edit] Parameters
first, last | - | the range of elements to generate | ||||||
g | - | generator function object that will be called. The signature of the function should be equivalent to the following:
The type Ret must be such that an object of type ForwardIt can be dereferenced and assigned a value of type Ret. |
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Type requirements | ||||||||
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ForwardIt must meet the requirements of ForwardIterator .
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[edit] Return value
(none)
[edit] Complexity
Exactly std::distance(first, last) invocations of g()
and assignments.
[edit] Possible implementation
template<class ForwardIt, class Generator> void generate(ForwardIt first, ForwardIt last, Generator g) { while (first != last) { *first++ = g(); } } |
[edit] Example
The following code fills a vector with random numbers:
Run this code
#include <algorithm> #include <iostream> #include <cstdlib> int main() { std::vector<int> v(5); std::generate(v.begin(), v.end(), std::rand); // Using the C function rand() std::cout << "v: "; for (auto iv: v) { std::cout << iv << " "; } std::cout << "\n"; // Initialize with default values 0,1,2,3,4 from a lambda function // Equivalent to std::iota(v.begin(), v.end(), 0); int n(0); std::generate(v.begin(), v.end(), [&n]{ return n++; }); std::cout << "v: "; for (auto iv: v) { std::cout << iv << " "; } std::cout << "\n"; }
Possible output:
v: 52894 15984720 41513563 41346135 51451456 v: 0 1 2 3 4
[edit] See also
assigns a range of elements a certain value (function template) |
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saves the result of N applications of a function (function template) |
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(parallelism TS)
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parallelized version of std::generate (function template) |