void String::insert(int start, const String& s)
{
        //save old values
        char* temp = new char[size+1];
        strcpy(temp, str);
        unsigned oldSize = size;

        //resize
        size += s.size;
        str = new char[size + 1];

        //Counter
        unsigned tempCount = 0, // alt
                 sizeCount = 0; // neu

        while(tempCount < oldSize)
        {
            //if we reached the insertion-point...
            if(sizeCount == start)
            {
                //...insert the new string at this position
                for(unsigned sCount = 0; sCount < s.size; sCount++)
                {
                    //mit neuen Werten füllen
                    str[sizeCount] = s.str[sCount];
                    sizeCount++;
                }
            }

        //fill with old values
        str[sizeCount] = temp[tempCount];
        sizeCount++;
        tempCount++;
        }

        //adding NULL-Byte
        str[size] = '\0';
        delete [] temp;

}