swap函数
语法:
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void swap(vector& __x); |
swap() 交换两个Vector
源代码
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/** * @brief Swaps data with another %vector. * @param x A %vector of the same element and allocator types. * * This exchanges the elements between two vectors in constant time. * (Three pointers, so it should be quite fast.) * Note that the global std::swap() function is specialized such that * std::swap(v1,v2) will feed to this function. */ void swap(vector& __x) { std::swap(this->_M_impl._M_start, __x._M_impl._M_start); std::swap(this->_M_impl._M_finish, __x._M_impl._M_finish); std::swap(this->_M_impl._M_end_of_storage, __x._M_impl._M_end_of_storage); } |
测试代码
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// 梁笔记 // https://zouzhongliang.com #include <iostream> #include <vector> using namespace std; int main() { vector<int> v1; vector<int> v2(3, 2); v1.push_back(1); v1.push_back(2); v1.push_back(3); v1.push_back(4); v1.push_back(5); cout<<"v1向量骨元素数："<<v1.size()<<endl; cout<<"v2向量骨元素数："<<v2.size()<<endl; v1.swap(v2); //交换 cout<<"v1向量骨元素数："<<v1.size()<<endl; cout<<"v2向量骨元素数："<<v2.size()<<endl; } |
测试结果：
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v1向量骨元素数：5 v2向量骨元素数：3 v1向量骨元素数：3 v2向量骨元素数：5 |