VB.NET文件名排序輕松掌握
作者：佚名
VB.NET文件名排序這一算法在實際應(yīng)中是一個比較重要的操作步驟。對于初學者來說，需要再學習的過程中對此加強關(guān)注。
VB.NET編程語言的應(yīng)用，幫助開發(fā)人員在一定程度上提高了程序開發(fā)效率。而且其應(yīng)用范圍比較廣泛，使用技巧多樣化。比如在對文件的操作上就能夠體會到它的功能強大性。首先讓我們一起來了解一下VB.NET文件名排序的相關(guān)算法。
輸入 ： a1,a2,a10,a001
我們知道，如果按照字符串比較,結(jié)果應(yīng)該是 a001,a1,a10,a2,但我們期望的結(jié)果應(yīng)該是a001,a1,a2,a10.
自己寫了一個VB.NET文件名排序的算法，請參考，或者有更好的算法，請賜教
- /*
- 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;
- }
VB.NET文件名排序的相關(guān)算法就為大家介紹到這里。
【編輯推薦】
責任編輯：曹凱
來源：
中國IT實驗室
