十进制跟十六进制的字符串互转

void StrDec2BufDec(const StrVal& strDec, BYTE* bufDec) {
    for (size_t i = 0; i < strDec.length(); ++i) {
        bufDec[i] = 0;
        if (strDec[i] >= L'0' && strDec[i] <= L'9')
            bufDec[i] = strDec[i] - L'0';
    }
}

int StrDec2HexBuf( const StrVal& strDec, BYTE* destBuf ) {
    size_t nIndex = 0;
    while (nIndex < strDec.length() && (strDec[nIndex] <= '0' || strDec[nIndex] > '9'))
        ++nIndex;
    if (nIndex >= strDec.length())
        return 0;

    size_t nDecLen = strDec.length() - nIndex;
    BYTE* decBuf = new BYTE[nDecLen+1];
    memset(decBuf, 0, nDecLen+1);
    StrDec2BufDec(StrVal(strDec, nIndex), decBuf);

    BYTE* hexBuf = new BYTE[nDecLen];
    memset(hexBuf, 0, nDecLen);
    BYTE nTemp = 0;
    for (size_t nDecIndex = 0; nDecIndex < nDecLen; ++nDecIndex) {
        nTemp = 0;
        for (int nBitIndex = 0; nBitIndex < 8; ++nBitIndex) {
            for (size_t nStartIndex = nDecIndex; nStartIndex < nDecLen; ++nStartIndex) {
                decBuf[nStartIndex+1] += (decBuf[nStartIndex]&0x01) == 1?10:0;
                decBuf[nStartIndex] >>= 1;
            }
            nTemp |= decBuf[nDecLen] > 0? (1 << nBitIndex):0;
            decBuf[nDecLen] = 0;
        }
        hexBuf[nDecIndex] = nTemp;
    }

    while (nDecLen > 0) {
        if (hexBuf[--nDecLen] > 0)
            break;
    }

    if (destBuf != NULL)
        memcpy(destBuf, hexBuf, nDecLen+1);

    delete [] decBuf;
    delete [] hexBuf;

    return nDecLen + 1;
}

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以上是10进制转16进制的代码，可以调用int StrDec2HexBuf( const StrVal& strDec, BYTE* destBuf )，将strDec的十进制数据转换成16进制的destBuf字符串，并返回destBuf的有效长度

关于10进制转16进制的方法：

1、我这里先将strDec转换成以每个字节代表一个数字的方法表示的方式。然后再进行相应的转换。void StrDec2BufDec(const StrVal& strDec, BYTE* bufDec)

2、关于十进制转16进制，我是将十进制转换成2进制的方式。即对每个数字进行除2取余的方式。具体关于十进制转16进制方法很多，我用转换成2进制只是其中一种方法。

#include <string>
typedef std::wstring StrVal;

int CalcStep(byte* cur, int nCurLen) {
    int nTemp = 0;
    for (int nIndex = 0; nIndex < nCurLen; ++nIndex) {
        nTemp += cur[nIndex] * 256;
        cur[nIndex] = nTemp % 10;
        nTemp /= 10;
    }

    while (nTemp > 0) {
        cur[nCurLen++] = nTemp % 10;
        nTemp /= 10;
    }

    return nCurLen;
}

void MulOneByte(byte* dec, int data, byte* base, int nBaseLen) {
    for (int nBaseIndex = 0; nBaseIndex < nBaseLen; ++nBaseIndex) {
        int nTemp = data * base[nBaseIndex];
        for (int nDecIndex = nBaseIndex; nTemp > 0; ++nDecIndex) {
            nTemp += dec[nDecIndex];
            dec[nDecIndex] = nTemp % 10;
            nTemp /= 10;
        }
    }
}

void Hex2Dec(byte* hexBuf, int nHexLen, byte* decBuf) {
    byte* base = new byte[nHexLen*4];
    memset(base, 0, nHexLen*4);
    base[0] = 1;
    int nCurBaseLen = 1;

    for (int nHexIndex = 0; nHexIndex < nHexLen; ++nHexIndex) {
        MulOneByte (decBuf, hexBuf[nHexIndex], base, nCurBaseLen);
        nCurBaseLen = CalcStep(base, nCurBaseLen);
    }
}

//////////////////////////////////////////////////////////////////////////
StrVal Convert2DecData(BYTE* srcData, int nLen) {
    StrVal destStr;

    int nDecLen = nLen*4;
    BYTE* decData = new BYTE[nDecLen];
    memset(decData, 0, nDecLen);
    Hex2Dec(srcData, nLen, decData);

    while (nDecLen-- > 0) {
        if (decData[nDecLen] > 0)
            break;
    }
    wchar_t midBuf[MAX_PATH];
    while (nDecLen >= 0) {
        swprintf_s(midBuf, MAX_PATH, L"%d", decData[nDecLen--]);
        destStr.append(midBuf);
    }

    delete [] decData;

    return destStr;
}

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上面代码是将16进制转成10进制的字符串

在void Hex2Dec(byte* hexBuf, int nHexLen, byte* decBuf)这里，我也是将结果以decBuf的每个字节代表一个0~9的数字，这里我new了一个比十六进制缓冲区大4倍的缓冲区来存放数据。（经计算3倍应该够了）

首先调用void MulOneByte(byte* dec, int data, byte* base, int nBaseLen)

我的base[]初始值为1，然后再乘以hexBuf的每个字节。计算结果再加到dec[]

CalcStep则是为base缓冲区的值（以10进制表示）乘以256

因为Hex2Dec中，hexBuf每次以一个字节的进制从低位到高位进行计算，所以每次计算完成之后需要将base乘以256，然后将base调整成每个字节以10进制表示的形式。

最终

StrVal Convert2DecData(BYTE* srcData, int nLen)函数的显示。因为我的电脑是小端模式，所以从后往前进行打印输出。

额外添加自增的函数。具体自增方式可以再修改

void IncData( BYTE* val, INT64 nIncStep ) {
    BYTE* pIncStep = (BYTE*)&nIncStep;

    int nLeft = 0;
    for (int nIndex = 0; nIndex < sizeof(INT64); ++nIndex) {
        for (int nInner = 0; nInner < 8; ++nInner) {
            nLeft = nLeft + (val[nIndex] & (1<<nInner)) + (pIncStep[nIndex] & (1<<nInner));
            val[nIndex] &= ~(1 << nInner);
            val[nIndex] ^= (nLeft & (1<<nInner));
            nLeft &= 1 << (nInner+1);
        }
        nLeft >>= 8;
    }

    for (int nIndex = sizeof(INT64); nLeft > 0; ++nIndex) {
        for (int nInner = 0; nInner < 8 && nLeft > 0; ++nInner) {
            nLeft = nLeft + (val[nIndex] & (1 << nInner));
            val[nIndex] &= nLeft & (1 << nInner) & 0xff;
            nLeft &= 1 << (nInner+1);
        }
        nLeft >>= 8;
    }
}

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