typedef std::string AddressLines[4]定义了一个string数组，大小为4

int main()
{
    typedef std::string AddressLines[];

    std::string *pal = new std::string[];
    std::string *pal1 = new AddressLines;

    delete [] pal;
    delete [] pal1;

    return ;
}

typedef std::string AddressLines[]; 这样定义居然是代表AddressLines是一个string数组，4个string。

new std::string[] 和 new AddressLines 是同一个意思，删除时必须用delete[]