I'm making a program that is supposed to store the circles in a file, each circle should have an id and a radius.

after i Add some circles to the file i need to open it again and search for a specific Id to display it.

Here's what I've done so far. Please any help would be appreciated.

Circle.h

#ifndef CIRCLE_H
#define CIRCLE_H

#include <iostream>
using namespace std;

class Circle
{
	friend ostream& operator <<(ostream& output, const Circle& aCircle);
	friend istream& operator >>(istream& input, Circle& aCircle);

public:
	Circle();
	Circle(double radius, int id);
	Circle(const Circle& aCircle);
	~Circle();

	void SetCircleRadius(double radius) { _circleRadius = radius; }
	void SetCircleId(int id) { _circleId = id; }

	double GetCircleRadius() const { return _circleRadius; }
	int GetCircleId() const { return _circleId; }

	void FindCirlce()
	{
		cout << "\nEnter the Id of the circle you want to find ";
		cin >> _circleId;
	}

private:
	double _circleRadius;
	int	_circleId;
};

#endif

Circle.cpp

#include "Circle.h"

Circle::Circle()
{
	_circleId = 12345;
	_circleRadius = 0.0;
}

Circle::Circle(double radius, int id)
{
	_circleId = id;
	_circleRadius = radius;
}

Circle::Circle(const Circle &aCircle)
{
	_circleId = aCircle._circleId;
	_circleRadius = aCircle._circleRadius;
}

Circle::~Circle()
{
}

ostream& operator <<(ostream& output, const Circle& aCircle)
{
	output << "Circle Id: " << aCircle._circleId;
	output << "Circle Radius: " << aCircle._circleRadius;

	return (output);
}

istream& operator >>(istream& input, Circle& aCircle)
{
	int quantity;
	cout << "How many circles do you want to add ";
	input >> quantity;

	for (int i = 0; i < quantity; ++i)
	{
		cout << "\nEnter the ID of Circle #" << (i + 1) << " : ";
		input >> aCircle._circleId;

		cout << "Enter Radius of Circle #" << (i + 1) << " : ";
		input >> aCircle._circleRadius;

		cout << endl;
	}

	return (input);
}

main.cpp

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

#include "Circle.h"

int main ()
{
	Circle aCircle;
	fstream file;
	int option;

	file.open("Circle.txt", ios::in);

	if (file.fail())
	{
		cout << "\n\nError: failed to open file.\n\n";
	}
	else
	{
		file.read((char*)& aCircle, sizeof(aCircle));

		while (!file.eof())
		{
			file.read((char*)& aCircle, sizeof(aCircle));
		}
		file.close();
	}

	do
	{
		cout << "Menu \n"
			 << " (1) Add Circle(s) \n"
			 << " (2) Find a Circle by ID \n"
			 << " (3) Exit \n";

		cin >> option;
		switch (option)
		{
		case 1:
			cin >> aCircle;
			break;


		case 2:
			file.open("Circle.txt", ios::in);
			file.read((char*)& aCircle, sizeof(aCircle));
			aCircle.FindCirlce();

			break;


		case 3:
			file.clear();
			file.open("Circle.txt", ios::out);

			if (!file.fail())
			{
				file.write((char*)& aCircle, sizeof(aCircle));

				file.close();

				cout << "\n\nGoodbye . . .\n\n";
			}
			else
				cerr << "\n\nERROR: The archive couldn't be opened\n\n";
			break;

		default:
			cerr << "\nERROR: Wrong Option menu.\n\n";

		}

	} while (option != 3);

	return EXIT_SUCCESS;
}

i would suggest you load the contents of the file in a map either in the beginning or when the user chooses option 2 and then when the user enters the Id of the circle, fetch the corresponding circle details and print it ..

Thank you for your help. But I'm new to this file I/O thing. Could you give me a simple code example explaining what you mean. For instance what do you mean by "load the contents of the file in a map" and "fetch the corresponding circle details"

i wish i could.. but i'm kind of busy right now.. to help you move ahead i can tell you what to do..

take STL documentation and read about maps , they are containers that can store key/value pairs.

then read the contents of the file using

inFile >> elem; this will read till next white space, since i dont know how ur file is arranged, i think this will work..

once you have the id/radius pair, insert it in the map. then you can use the 'find' method on the map to get the corresponding radius..

and i realised that you will have to do this everytime the user takes option 2, coz the user might have added more entries to the file in between...

and it just struck me that since this step is done everytime you might as well not do it all and instead keep comparing the values as and when you read from the file without inserting in the map ... sorry if i confused you :)

forgot to mention. I don't need to make a collection of circles, the file it self stores the circles I only need to search for 1 file and print it.

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