multimap::erase
描述 (Description)
C ++函数std::multimap::erase()删除与键k关联的映射值。
声明 (Declaration)
以下是std :: multimap :: erase()函数形式std :: map头的声明。
C++98
size_type erase (const key_type& k);
C++11
size_type erase (const key_type& k);
参数 (Parameters)
k - 要删除的元素的键。
返回值
返回删除的元素数。
异常 (Exceptions)
如果抛出异常,对容器没有影响。
时间复杂
对数即O(log n)
例子 (Example)
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},
};
size_t ret;
cout << "Multimap contains following elements before erase operation" << endl;
for (auto it = m.begin(); it != m.end(); ++it)
cout << it->first << " = " << it->second << endl;
cout << endl;
ret = m.erase('a');
cout << "Number of value removed are = " << ret << endl;
cout << endl;
cout << "Multimap contains following elements after erase operation" << endl;
for (auto it = m.begin(); it != m.end(); ++it)
cout << 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
Number of value removed are = 2
Multimap contains following elements after erase operation
b = 3
c = 4
c = 5