erator[]( const Key& key );``
- ``const_reference  operator[]( const Key& key ) const;``

    - Requirements: the key exists

    - Effects: returns the object with key ``key``

    - Throws: ``bad_ptr_container_operation`` if the key does not exist -->
</div>
<div class="section" id="semantics-pointer-container-requirements">
<span id="pointer-container-requirements"></span><h2>Semantics: pointer container requirements</h2>
<ul>
<li><p class="first"><tt class="docutils literal">void transfer( iterator obje