判断QString是否为纯数字，查找自身最长重复子字符串

1.判断QString是否为纯数字

bool IsDigitString(QString strSource)
{
    bool bDigit = false;

    if (strSource.isEmpty())
    {
        return bDigit;
    }

    QByteArray strByteArray = strSource.toLatin1();
    const char *chString = strByteArray.data();

    while (*chString && *chString>='0' && *chString<='9') chString++;

    if (*chString)
    {
        bDigit = false;
    }
    else
    {
        bDigit = true;
    }

    return bDigit;
}

2.查找自身最长重复子字符串

QString MaxSubString(QString inputString)
{
    QString subString = "";
    int strLen = inputString.size();

    if  (strLen  <=  0)
    {
        return subString;
    }

    int maxSubStrLen = 0;
    int tempLen = 0;
    int subIndex = 0;
    int i = 0;
    int j = 0;
    int k = 0;

    while (i <  strLen)
    {
        j = i+1;
        while(j < strLen)
        {
            if  (inputString.at(i)  ==  inputString.at(j))
            {
                tempLen = 1;
                for (k=1;  j+k<strLen && inputString.at(i+k)==inputString.at(j+k);  k++)
                {
                    tempLen++;
                }

                if  (tempLen  >  maxSubStrLen)
                {
                    subIndex = i;
                    maxSubStrLen = tempLen;
                }

                j += tempLen;
            }
            else
            {
                   j++;
            }
        }
        i++;
    }

    for  (i=0;  i<maxSubStrLen;  i++)
    {
        subString.append(inputString.at(subIndex+i));
    }

    return subString;
}

https://www.cnblogs.com/sz-leez/p/6537004.html