function template
<algorithm>
std::iter_swap
template <class ForwardIterator1, class ForwardIterator2>
void iter_swap (ForwardIterator1 a, ForwardIterator2 b);
Exchange values of objects pointed to by two iterators
Swaps the elements pointed to by a and b.
The function calls swap (unqualified) to exchange the elements.
The behavior of this function template is equivalent to:
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template <class ForwardIterator1, class ForwardIterator2>
void iter_swap (ForwardIterator1 a, ForwardIterator2 b)
{
swap (*a, *b);
}
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Parameters
- a, b
- Forward iterators to the objects to swap.
swap shall be defined to exchange values of the type pointed to by the iterators.
Example
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// iter_swap example
#include <iostream> // std::cout
#include <algorithm> // std::iter_swap
#include <vector> // std::vector
int main () {
int myints[]={10,20,30,40,50 }; // myints: 10 20 30 40 50
std::vector<int> myvector (4,99); // myvector: 99 99 99 99
std::iter_swap(myints,myvector.begin()); // myints: [99] 20 30 40 50
// myvector: [10] 99 99 99
std::iter_swap(myints+3,myvector.begin()+2); // myints: 99 20 30 [99] 50
// myvector: 10 99 [40] 99
std::cout << "myvector contains:";
for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';
return 0;
}
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Output:
myvector contains: 10 99 40 99
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Complexity
Constant: Calls swap once.
Data races
The objects pointed to by both iterators are modified.
Exceptions
Throws if the call to swap throws.
Note that invalid arguments cause undefined behavior.
See also
- swap
- Exchange values of two objects (function template
)
- copy
- Copy range of elements (function template
)
- replace
- Replace value in range (function template
)