struct SortS which 
{
Int nNum; 
String strName; 

Bool bFlag;//false - & gt; According to the num is true - & gt; According to the Name is 

SortS () : nNum (0), strName (" "), bFlag (false) 
{} 

Bool operator<(const SortS & amp; Const stSortS) 
{
Bool bRet=false; 
if(! BFlag & amp; & ! StSortS. BFlag) 
{
BRet=nNum & lt; StSortS. NNum; 
} 
The else 
{
BRet=strName & lt; StSortS. StrName;//??? 
} 

Return bRet. 
} 
}; 


Int main () 
{
Map MapSortTest; 

SortS stSort1; 
StSort1. NNum=1; 
StSort1. StrName="111"; 

SortS stSort2; 
StSort2. NNum=2; 
StSort2. StrName="222"; 

SortS stSort3; 
StSort3. NNum=3; 
StSort3. StrName="333"; 

SortS stSort4; 
StSort4. NNum=4; 
StSort4. StrName="444"; 

MapSortTest. Insert (pair (stSort1, "liu111")); 
MapSortTest. Insert (pair (stSort2, "liu222")); 
MapSortTest. Insert (pair (stSort3, "liu333")); 
MapSortTest. Insert (pair (stSort4, "liu444")); 

Map : : iterator it=mapSortTest. The begin (); 
For (; It!=mapSortTest. End (); + + it) 
{
Printf (" it. First: second: % d % s % s \ n ", it - & gt; First, nNum, it - & gt; First, strName c_str (), 
It - & gt; Second. C_str ()); 
} 
Printf (" \ n \ n "); 

SortS stSort5; 
StSort5. BFlag=true; 
StSort5. StrName="222"; 
It=mapSortTest. Find (stSort5); 

If (it==mapSortTest. End ()) 
{
Printf (" 66666666666666666666666666666 \ n "); 
} 
The else 
{
Printf (" 77777777777777777777777777777 \ n "); 
} 

It=mapSortTest. The begin (); 
For (; It!=mapSortTest. End (); + + it) 
{
Printf (" it. First: second: % d % s % s \ n ", it - & gt; First, nNum, it - & gt; First, strName c_str (), 
It - & gt; Second. C_str ()); 
} 

system("pause"); 
return 0; 
} 

In the above code??? , if my collation using & gt; The find of the map will be can not find, but if the collation use & lt; Num (and above), the find of the map. Then you will find,,, now can't understand, ask god to explain,,,