一個查詢字串中包含的最長的數字子串的函數

#include <string>
#include <iostream>

#include <conio.h>

using namespace std;

struct strNode
{
const char* pStr;
int nMax;
strNode():pStr( NULL ), nMax( 0 ){}
};
bool isNumChar( const char* pStr )
{
if ( ( *pStr == '0' )  || ( *pStr == '1' ) || ( *pStr == '2' )
|| ( *pStr == '3') || ( *pStr == '4' ) || ( *pStr == '5') 
|| ( *pStr == '6') || ( *pStr == '7' ) || ( *pStr == '8')
|| ( *pStr == '9' ))
{
return true;
}
else
{
return false;
}
}
void FindMaxNumSubString( string& str, strNode& strNum )
{
const char* pStr = str.c_str();
int nMax;//= 0;
const char* pStrTemp = NULL;

while ( NULL != *pStr )
{
if ( isNumChar( pStr ))
{
nMax = 0;
nMax++;
pStrTemp = pStr;
while(( ++pStr ) && ( NULL != *pStr ))
{
if ( isNumChar( pStr ))
{
nMax++;
}
else
{
++pStr;
break;
}
}
if ( strNum.nMax < nMax )
{
strNum.nMax = nMax;
strNum.pStr = pStrTemp;
}
}
else
{
++pStr;
}
}

}

int main( int argc, char* argv[] )
{
string str( "abc2012dcb201jhg2012980221bcd12k" );//""

strNode strNum;

FindMaxNumSubString( str, strNum );

char* a = new char[strNum.nMax+1];// = { 0 };
memset( a, 0, strNum.nMax+1 );
str.copy( a,  strNum.nMax, str.length() - string( strNum.pStr ).length()  );
cout << a << endl;
_getch();
return 0;
}