map::empty (STL/CLR)

测试元素不存在。

    bool empty();

备注

成员函数返回 true 一个空序列控制。 它与() == 0等效。map::size (STL/CLR) 您可用它测试映射是否为空。

示例

// cliext_map_empty.cpp 
// compile with: /clr 
#include <cliext/map> 
 
typedef cliext::map<wchar_t, int> Mymap; 
int main() 
    { 
    Mymap c1; 
    c1.insert(Mymap::make_value(L'a', 1)); 
    c1.insert(Mymap::make_value(L'b', 2)); 
    c1.insert(Mymap::make_value(L'c', 3)); 
 
// display contents " [a 1] [b 2] [c 3]" 
    for each (Mymap::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

页眉： </cliext 映射>

命名空间： cliext

请参见

参考

map (STL/CLR)

map::size (STL/CLR)