替换空格

void replace(char* data, int length)
{
    if (data == nullptr || length <= 0)
        return;

    int nEmptyNumber = 0;
    int nOrignialLength = 0;
    int i = 0;
    while(data[i] != '\0')
    {
        if(data[i] == ' ')
            ++nEmptyNumber;
        ++i;
        ++nOrignialLength;
    }

    int nReplaceLength = nOrignialLength + nEmptyNumber * 2;
    if (nReplaceLength <= nOrignialLength || nReplaceLength > length)
        return;

    int nIndexReplace = nReplaceLength;
    while (i >= 0 && nIndexReplace > i)
    {
        if (data[i] == ' ')
        {
            data[nIndexReplace--] = '0';
            data[nIndexReplace--] = '2';
            data[nIndexReplace--] = '%';
        }
        else
            data[nIndexReplace--] = data[i];
        --i;
    }
    return;
}