multimap::empty (STL/CLR)

测试元素是否存在。

    bool empty();

备注

由一个空序列控制，则成员函数返回 true。 它等效于multimap::size (STL/CLR)() == 0。 使用它来测试 hash_set 是否为空。

示例

// cliext_multimap_empty.cpp 
// compile with: /clr 
#include <cliext/map> 
 
typedef cliext::multimap<wchar_t, int> Mymultimap; 
int main() 
    { 
    Mymultimap c1; 
    c1.insert(Mymultimap::make_value(L'a', 1)); 
    c1.insert(Mymultimap::make_value(L'b', 2)); 
    c1.insert(Mymultimap::make_value(L'c', 3)); 
 
// display contents " [a 1] [b 2] [c 3]" 
    for each (Mymultimap::value_type elem in c1) 
        System::Console::Write(" [{0} {1}]", elem->first, elem->second); 
    System::Console::WriteLine(); 
    System::Console::WriteLine("size() = {0}", c1.size()); 
    System::Console::WriteLine("empty() = {0}", c1.empty()); 
 
// clear the container and reinspect 
    c1.clear(); 
    System::Console::WriteLine("size() = {0}", c1.size()); 
    System::Console::WriteLine("empty() = {0}", c1.empty()); 
    return (0); 
    } 
 

要求

标头: <cliext/map>

Namespace: cliext

请参见

参考

multimap (STL/CLR)

multimap::size (STL/CLR)