Hash_map & lt; CTest, int, MyHashCompare> CHash; 

Struct IHashable 
{
Virtual unsigned long hash_value (const)=0; 
Virtual Boolean operator & lt; (const IHashable& Val) const=0; 
Virtual IHashable& Operator=(const IHashable& Val)=0; 
}; 

The class CTest: public IHashable 
{
Public: 
Int m_value; 
Cstrings m_message; 
Public: 
CTest () : m_value (0) {} 

CTest (const CTest& Obj) 
{
M_value=https://bbs.csdn.net/topics/obj.m_value; 
M_message=obj. M_message; 
} 
Public: 
Virtual IHashable& Operator=(const IHashable& Val) {
M_value=https://bbs.csdn.net/topics/(CTest & val). M_value; 
M_message=((CTest&) Val). M_message; 
Return (* this); 
} 

Virtual unsigned long hash_value () const {
//is used here in the class m_value domain to calculate the hash value, can also use more complex function to calculate all the domain general hash value 
Return (m_value ^ 0 xdeadbeef); 
} 

Virtual Boolean operator & lt; (const IHashable& Val) const {
Return (m_value & lt; ((CTest&) Val) m_value); 
} 
}; 

TemplateThe class MyHashCompare: public hash_compare & lt; _Tkey & gt; 
{
Public: 
Size_t operator () (const _Tkey & amp; _Key) const {
Return (_Key hash_value ()); 
} 


Boolean operator () (const _Tkey & amp; _Keyval1, const _Tkey & amp; _Keyval2) const {
Return (comp (_Keyval1 _Keyval2)); 
} 
};