Saving the array of structures

[En1ro]

The problem is that i need to save in simple way the array of structure:

struct gydytojas {
   int gydid, amzius, specialyb, telefonas, asmkod;
   String vardas[25];
   String pavarde[35];
   String adresas[50]; };

    gydytojas gydmas[100];

This is the struct & array.

Code:

gydytojas pgyd;
pgyd.vardas[25]=Edit21->Text;
pgyd.pavarde[35]=Edit22->Text;
pgyd.adresas[50]=Edit24->Text;
pgyd.asmkod=StrToInt(Edit23->Text);
pgyd.amzius=StrToInt(Edit27->Text);
pgyd.gydid=StrToInt(Edit26->Text);
pgyd.telefonas=StrToInt(Edit25->Text);
pgyd.specialyb=ComboBox5->ItemIndex;
gydmas[1]=pgyd;
ofstream fr("Gydytojai.inf");
for( int i = 1; i<2; i++) { fr << gydmas[i];}
fr.close();

(This is the creation of that file also, later i will ned to read and add the right number of array..)
I want to save an array to one file without using SaveDialog / OpenDialog( i can't choose file from which i could read/save so no printf, scanf could be used) , and would like to read from that file data.

As you see i tried to use ofstream, but there was an error :
[C++ Error] Unit1.cpp(180): E2094 'operator<<' not implemented in type 'ofstream' for arguments of type 'TForm1::gydytojas'

[Radical Edward]

You can still use ofstream, but you have to overload the << operator for your struct:

struct gydytojas {
  int gydid, amzius, specialyb, telefonas, asmkod;
  String vardas[25];
  String pavarde[35];
  String adresas[50];

  friend ostream& operator<<(ostream& os, const gydytojas& obj);
};

ostream& operator<<(ostream& os, const gydytojas& obj)
{
  // Print the members to os like you would to cout

  return os;
}

[En1ro]

You can still use ofstream, but you have to overload the << operator for your struct:

struct gydytojas {
  int gydid, amzius, specialyb, telefonas, asmkod;
  String vardas[25];
  String pavarde[35];
  String adresas[50];

  friend ostream& operator<<(ostream& os, const gydytojas& obj);
};

ostream& operator<<(ostream& os, const gydytojas& obj)
{
  // Print the members to os like you would to cout

  return os;
}

Thanks for explanation, but after i add

ostream& operator <<(ostream& os, const gydytojas& obj) 
{

return os;
}

Get this error.
[C++ Error] Unit1.h(234): E2080 'TForm1::operator <<(ostream &,const TForm1::gydytojas &)' must be declared with one parameter

And if i need to read that from that file i should create another friend istream& operator, right?

[Radical Edward]

It looks like what you did is add the overloaded operator as a member function instead of a friend, and that's different from Ed's code.

[En1ro]

It looks like what you did is add the overloaded operator as a member function instead of a friend, and that's different from Ed's code.

Abit confused, so where i should put this thing ?

ostream& operator<<(ostream& os, const gydytojas& obj)
{
  // Print the members to os like you would to cout

  return os;
}

I thought, it should be in private declaration of Unit1.h.

[Radical Edward]

Edward showed you exactly where to put it. But you can make it even simpler like this:

struct gydytojas {
  int gydid, amzius, specialyb, telefonas, asmkod;
  String vardas[25];
  String pavarde[35];
  String adresas[50];

  friend ostream& operator<<(ostream& os, const gydytojas& obj)
  {
    // Print the members to os like you would to cout

    return os;
  }
};

Don't forget the friend keyword or you'll get the same error saying there are too many parameters.

[En1ro]

Edward showed you exactly where to put it.

Yes, i did what you said in your first post, and then i got that error.

[ But you can make it even simpler like this:

struct gydytojas {
  int gydid, amzius, specialyb, telefonas, asmkod;
  String vardas[25];
  String pavarde[35];
  String adresas[50];

  friend ostream& operator<<(ostream& os, const gydytojas& obj)
  {
    // Print the members to os like you would to cout

    return os;
  }
};

Don't forget the friend keyword or you'll get the same error saying there are too many parameters.

Yep, that works! Thanks, just one question, after i write that info to that file, should that file would be empty? ;s

[Radical Edward]

The file shouldn't be empty, but you should also actually be writing something in the overloaded operator. Replace the comment with code to write your struct's data members to os.

[En1ro]

Ah..Could you suggest any example of syntax, because all, that I've tried was bad..

[mitrmkar]

Below is an arbitrary example, hope it gives some insight

#include <fstream>
#include <string>
using namespace std;

class MyClass
{
	string 	strings[2];
	int 	value;
	friend ostream & operator << (ostream & stream, const MyClass & obj);

public:
	MyClass(const string & s1, const string & s2, const int n)
	{
		strings[0] = s1;
		strings[1] = s2;
		value = n;
	}
};

ostream & operator << (ostream & stream, const MyClass & obj)
{
    // because this overload is a friend of MyClass,
    // the access to private class members is possible here

    // stuff in the two strings + the integer value, separated by tabs
	stream
		<< obj.strings[0]
		<< "\t"
		<< obj.strings[1]
		<< "\t"
		<< obj.value
		<< "\n";

	return stream;
}

int main()
{
	MyClass test("String #1", "String #2", 123);

	ofstream ofs("c:\\temp\\o.txt");	
	ofs << test;

	return 0;
}

You probably need to overload the ostream operator << for AnsiString too.