swap函数
语法:
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void swap(set<_Key,_Compare,_Alloc>& __x); |
swap()交换两个集合变量
源代码
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/** * @brief Swaps data with another %set. * @param x A %set of the same element and allocator types. * * This exchanges the elements between two sets in constant time. * (It is only swapping a pointer, an integer, and an instance of * the @c Compare type (which itself is often stateless and empty), so it * should be quite fast.) * Note that the global std::swap() function is specialized such that * std::swap(s1,s2) will feed to this function. */ void swap(set<_Key,_Compare,_Alloc>& __x) { _M_t.swap(__x._M_t); } |
测试代码
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// 梁笔记 // https://zouzhongliang.com #include <iostream> #include <set> using namespace std; int main() { set<int> s1,s2; s1.insert(10); s1.insert(12); s1.insert(13); s1.insert(9); s2.insert(1); s2.insert(2); s2.insert(5); s2.insert(4); s2.insert(6); cout<<"s1集合中元素："<<endl; set<int>::iterator iter = s1.begin(); for(iter;iter!=s1.end();iter++){ cout<<*iter<<" "; } cout<<endl; cout<<"s2集合中元素："<<endl; iter = s2.begin(); for(iter;iter!=s2.end();iter++){ cout<<*iter<<" "; } cout<<endl; s1.swap(s2); //交换两集合 cout<<"交换后s1集合中元素："<<endl; iter = s1.begin(); for(iter;iter!=s1.end();iter++){ cout<<*iter<<" "; } cout<<endl; cout<<"交换后s2集合中元素："<<endl; iter = s2.begin(); for(iter;iter!=s2.end();iter++){ cout<<*iter<<" "; } cout<<endl; } |
测试结果：
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s1集合中元素： 9 10 12 13 s2集合中元素： 1 2 4 5 6 交换后s1集合中元素： 1 2 4 5 6 交换后s2集合中元素： 9 10 12 13 |