输入 ： a1,a2,a10,a001
我们知道，如果按照字符串比较,结果应该是 a001,a1,a10,a2,但我们期望的结果应该是a001,a1,a2,a10.
自己写了一个算法，请参考，或者有更好的算法，请赐教
/*
Return Value Description
< 0 arg1 less than arg2
0 arg1 equivalent to arg2
> 0 arg1 greater than arg2
*/
int compare(const void* arg1,const void* arg2)
{
if (NULL==arg1||NULL==arg2)//address of item
return 0;
LPSTR lpText1 = *( TCHAR** )arg1; //content of item
LPSTR lpText2 = *( TCHAR** )arg2; //content of item
if (NULL==lpText1||NULL==lpText2)
return 0;
int nText1Len = _tcslen(lpText1);
int nText2Len = _tcslen(lpText2);
int nText1IndexHandled = 0;
int nText2IndexHandled = 0;
int nRet = 0;
for (;;)
{
if (nText1IndexHandled==nText1Len||nText2IndexHandled==nText2Len) //don't compare complete since all are same, "ab","abc"
{
TCHAR chOffset1 = nText1IndexHandled<nText1Len?lpText1[nText1IndexHandled]:0;
TCHAR chOffset2 = nText2IndexHandled<nText2Len?lpText2[nText2IndexHandled]:0;
nRet = (int)((WORD)chOffset1-(WORD)chOffset2);
break;
}
TCHAR ch1 = *(lpText1+nText1IndexHandled);
TCHAR ch2 = *(lpText2+nText2IndexHandled);
if (isdigit(ch1)&&isdigit(ch2)) // if digit, change to number and compare
{
TCHAR* lpNum1 = new TCHAR[nText1Len];
TCHAR* lpNum2 = new TCHAR[nText2Len];
if (NULL==lpNum1||NULL==lpNum2)
return 0;
memset(lpNum1,0,nText1Len*sizeof(TCHAR));
memset(lpNum2,0,nText2Len*sizeof(TCHAR));
extractnumber(lpText1,nText1Len,nText1IndexHandled,lpNum1);
extractnumber(lpText2,nText2Len,nText2IndexHandled,lpNum2);
nRet = comparenumber(lpNum1,lpNum2);
delete[] lpNum1;
delete[] lpNum2;
}
else
{
nRet = (int)((WORD)ch1-(WORD)ch2);
nText1IndexHandled++;
nText2IndexHandled++;
}
if (nRet!=0)
break;
}
return nRet;
}
TCHAR* extractnumber(TCHAR* lpBuf,int nLen,int& nIndexBegin,TCHAR* lpNumber)
{
if (NULL==lpBuf||NULL==lpNumber)
return lpNumber;
for (int i=nIndexBegin,nIndex=0;i<nLen;++i,++nIndexBegin)
{
TCHAR ch = *(lpBuf+i);
if (!isdigit(ch))
break;
lpNumber[nIndex++]=ch;
}
return lpNumber;
}
int comparenumber(TCHAR* lpNumber1,TCHAR* lpNumber2)
{
if (NULL==lpNumber1||NULL==lpNumber2)
return 0;
int nNum1Len = _tcslen(lpNumber1);
int nNum2Len = _tcslen(lpNumber2);
int nMaxLen = max(nNum1Len,nNum2Len);
TCHAR* lpFormatNum1 = new TCHAR[nMaxLen+1];
TCHAR* lpFormatNum2 = new TCHAR[nMaxLen+1];
if (NULL==lpFormatNum1||NULL==lpFormatNum2)
return 0;
memset(lpFormatNum1,_T('0'),nMaxLen*sizeof(TCHAR));
memset(lpFormatNum2,_T('0'),nMaxLen*sizeof(TCHAR));
lpFormatNum1[nMaxLen]=0;
lpFormatNum2[nMaxLen]=0;
int nPos = 0, nRet = 0;
int nIndex = nMaxLen-1;
for (nPos=nNum1Len-1;nPos>=0;--nPos)
lpFormatNum1[nIndex--]=lpNumber1[nPos];
nIndex = nMaxLen-1;
for (nPos=nNum2Len-1;nPos>=0;--nPos)
lpFormatNum2[nIndex--]=lpNumber2[nPos];
for (nPos=0;nPos<nMaxLen;++nPos)
{
nRet = lpFormatNum1[nPos]-lpFormatNum2[nPos];
if (nRet!=0)
break;
}
delete[] lpFormatNum1;
delete[] lpFormatNum2;
return nRet;
}
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