> I have a question, first time I use this. So ok I just started using
> FLTK
It seems you also started using C++.
> #include<string.h>
This is an old header file, you should use "#include <string>" without
".h" to get the current STL library.
> struct TPerson { char name[255]; char vorname[255]; char email[255];
> }P;
Urgs!
struct TPerson
{
string name;
string vorname;
string email;
void read(istream& In)
{
std::getline(In, name, '\0');
std::getline(In, vorname, '\0');
std::getline(In, email, '\0');
}
void write(ostream& Out) const
{
Out << name << '\0';
Out << vorname << '\0';
Out << email<< '\0';
}
};
Don't use char or char* if you can use string - you can be sure that
sometimes on overflow or another error will appear - to me it is
outdated style of programming.
If you are defining an object that is ment to be read or written, it
should now how to read/write itself, so these functions should be part
of the object. There are some other possibilities to read/write strings,
the example uses zero terminated strings.
> strcpy(P.name,i->value());
Yes, this is exactly the way to write worst software - if you don't have
a chance to avoid char[], you should use strncpy(), or limit the length
of input. Using strings makes things more easy:
P.vorname= i->value(); // Reading Input
i->value(P.vorname.c_str()); // Preset Input
> ofstream datei("Personen.dat", ios::app);
That's not binary, but text mode:
ofstream datei("Personen.dat", ios::app | ios::binary);
> datei.write((char*)&P,sizeof(TPerson));
This writes the class including this-pointer, not only the data and will
crash, when you read classes containing virtual functions. Using other
kinds of data types you also can get problems with internal aligning -
it is more save to write each variable in particular, as shown above:
P.write(datei);
> Can anybody help me with that please? Thanks in advance :D
de.comp.lang.iso-c++ should be helpful for you.
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