Difference between revisions of "cpp/algorithm/swap"
m (r2.7.3) (Robot: Adding de, fr, it, ja, pt, zh) |
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| Line 94: | Line 94: | ||
| <!-- should demo proper use of swap with generic types, as in void swap(T& other) {using std::swap; swap(member, other.member);} , not just trivialities --> | | <!-- should demo proper use of swap with generic types, as in void swap(T& other) {using std::swap; swap(member, other.member);} , not just trivialities --> | ||
| code= | | code= | ||
| + | #include <algorithm> | ||
| + | #include <iostream> | ||
| + | |||
| + | int main() | ||
| + | { | ||
| + | int a = 5, b = 3; | ||
| + | |||
| + | //before | ||
| + | std::cout << a << ' ' << b << std::endl; | ||
| + | |||
| + | std::swap(a,b); | ||
| + | |||
| + | //after | ||
| + | std::cout << a << ' ' << b << std::endl; | ||
| + | |||
| + | } | ||
| output= | | output= | ||
| + | 5 3 | ||
| + | 3 5 | ||
}} | }} | ||
Revision as of 07:50, 10 December 2012
Template:ddcl list begin <tr class="t-dsc-header">
<td> </td><td></td>
<td>(since C++11)
</tr> <tr class="t-dcl ">
<td >void swap( T& a, T& b );
<td > (1) </td> <td class="t-dcl-nopad"> </td> </tr> <tr class="t-dcl ">
<td >void swap( T2 (&a)[N], T2 (&b)[N]);
<td > (2) </td> <td > (since C++11) </td> </tr> Template:ddcl list end
Exchanges the given values.
1) Swaps the values a and b.
2) Swaps the arrays a and b. In effect calls std::swap_ranges(a, a+N, b).
Contents |
Parameters
| a, b | - | the values to be swapped |
| Type requirements | ||
-T must meet the requirements of MoveAssignable and MoveConstructible.
| ||
-T2 must meet the requirements of Swappable.
| ||
Return value
(none)
Exceptions
1) std::is_nothrow_move_constructible<T>::value &&
std::is_nothrow_move_assignable<T>::value
Complexity
1) Constant
2) Linear in N
Specializations
Both custom specializations and overloads of the std::swap algorithm are allowed, but the overloads are generally preferred since specializations of a function template aren't allowed for template classes. Library functions always use the user-provided overloads when swapping, if they are found by argument-dependent lookup (as per Template:concept concept).
The following overloads are already provided by the standard library:
Example
Output:
5 3 3 5
