operator==

03-26-2002, 02:47 PM

I'm trying to overload the operator== from a struct that i have made. I hold the struct's in a std::list -->> list<Record>My_Rec_List;
-----------------------------------------------

Trying to do:
if ( iter == My_Rec_List.front() )

------------------------------------------------
what i have (defined in the struct):

friend bool operator==(Record r, const Record &IN2){
return r.First_number == IN2.First_number;
}

VC++ 6.0 error
--------------------
error C2678: binary '==' : no operator defined which takes a left-hand operand of type 'class std::list<struct Record,class std::allocator<struct Record> >::iterator' (or there is no acceptable conversion)
Error executing cl.exe.

03-26-2002, 03:26 PM

better yet,

writing the record....

what iter x is pointing to is what i need to write...

Writes garbage but the only thing i can get to compile

Code:

SfileS.write((char*)(&x), sizeof(Record));

Sorensen · 03-26-2002, 03:49 PM

>Trying to do:
if ( iter == My_Rec_List.front() ) <

You'll have to use the operator* on iter.

>what iter x is pointing to is what i need to write...<

You could overload operator>> and operator<< to read/write a Records elements to file.

03-26-2002, 04:42 PM

Quote:

You could overload operator>> and operator<< to read/write a Records elements to file.

Can i do that, but still write in Binary mode ?

Sorensen · 03-26-2002, 05:24 PM

No if you really need to read/write in binary, then you need to do something like -

Code:

#include <iostream>
#include <fstream>

using namespace std;

struct TwoInts
{
	int a;
	int b;
};

int main()
{
	ofstream os("ti.bin",ios::binary);
	TwoInts one={1,2};
	os.write((char *)&one,sizeof(one));
	os.close();

	ifstream is("ti.bin",ios::binary);
	TwoInts two;
	is.read((char*)&two,sizeof(two));

	cout << two.a << ' ' << two.b << '\n';

	return 0;
}

03-26-2002, 02:47 PM	#1
Unregistered Guest Posts: n/a	operator== I'm trying to overload the operator== from a struct that i have made. I hold the struct's in a std::list -->> list<Record>My_Rec_List; ----------------------------------------------- Trying to do: if ( iter == My_Rec_List.front() ) ------------------------------------------------ what i have (defined in the struct): friend bool operator==(Record r, const Record &IN2){ return r.First_number == IN2.First_number; } VC++ 6.0 error -------------------- error C2678: binary '==' : no operator defined which takes a left-hand operand of type 'class std::list<struct Record,class std::allocator<struct Record> >::iterator' (or there is no acceptable conversion) Error executing cl.exe.

03-26-2002, 03:26 PM	#2
Unregistered Guest Posts: n/a	better yet, writing the record.... what iter x is pointing to is what i need to write... Writes garbage but the only thing i can get to compile Code: SfileS.write((char*)(&x), sizeof(Record));

03-26-2002, 03:49 PM	#3
Sorensen Sénior Member Join Date: Jan 2002 Posts: 982	>Trying to do: if ( iter == My_Rec_List.front() ) < You'll have to use the operator* on iter. >what iter x is pointing to is what i need to write...< You could overload operator>> and operator<< to read/write a Records elements to file.
Sorensen is offline

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