C++ Multimap 库 - erase() 函数
描述
C++ 函数 std::multimap::erase() 从位置中删除多重映射的单个元素。
该成员函数将 multimap 的大小减一。
声明
以下是 std::multimap::erase() 函数形式 std::map 头的声明。
C++11
iterator erase (const_iterator position);
参数
position − 要移除的元素的迭代器。
返回值
返回最后一个移除元素之后的迭代器。
异常
如果抛出异常，对容器没有影响。
时间复杂度
Logarithmic i.e. O(log n)
示例
以下示例显示了 std::multimap::erase() 函数的用法。
#include <iostream>
#include <map>
using namespace std;
int main(void) {
/* Multimap with duplicates */
multimap<char, int> m {
{'a', 1},
{'a', 2},
{'b', 3},
{'c', 4},
{'c', 5},
};
cout << "Multimap contains following elements before erase operation" << endl;
for (auto it = m.begin(); it != m.end(); ++it)
cout << it->first << " = " << it->second << endl;
auto it = m.erase(m.begin());
cout << "Multimap contains following elements after erase operation" << endl;
for (auto it = m.begin(); it != m.end(); ++it)
cout << it->first << " = " << it->second << endl;
cout << "After erase operation iterator points to " << it->first
<< " = " << it->second << endl;
return 0;
}
让我们编译并运行上面的程序，这将产生以下结果 −
Multimap contains following elements before erase operation a = 1 a = 2 b = 3 c = 4 c = 5 Multimap contains following elements after erase operation a = 2 b = 3 c = 4 c = 5 After erase operation iterator points to a = 2
