Error: no appropriate default constructor available

[csonx_p]

C++ can be quite confusing for me... Haven't touched this file in weeks and it has been compiling with no probs,now today after having been growing my project by modifying other classes, i get an error from a class which hasn't been modified and has been compiling

here's part of the class

#include "Fleet.h"
#include <fstream>
#include <iostream>
#include <algorithm>
#include <conio.h>

using namespace std;

struct CAR_MAKE 
{ 
    string make; 
    string model;
};

Fleet::Fleet(): fleet() {}

Fleet::CarFleet Fleet::getFleet()
{
	return fleet;
}

// ---------------------------------------------------------------
// Implementing function to read fleet of cars from text file

void Fleet::ReadFleetFromFile()
{					
	char filename[MAX_PATH] ;

	puts("\n\nPlease enter the text file to open:\n");
	cin >> filename;

	istream fleetin; // Problem is here
	fleetin.open (filename);

	/* Ensure file was openned, otherwise send an error */
	if ( fleetin.fail() )
	{
		puts("");
		perror("ERROR! while trying to open file");
		exit(1);
	}
	else
	{
		Car car;	
		
		// Read in fleet records
		while ( !car.Read(fleetin) )
		{
			fleet.push_back(car);
			SortAlpha();		
		}
		
		// Did we read something?
		if( fleet.size()==0) {
			puts("\nData was unsuccessfully read !!...");
		}
		else
			puts("\nProcessed reading...");
	}

	fleetin.close();

}

/* ERROR 

: error C2512: 'std::basic_istream<_Elem,_Traits>' : no appropriate default constructor available
        with
        [
           _Elem=char,
           _Traits=std::char_traits<char>
        ]
: error C2039: 'open' : is not a member of 'std::basic_istream<_Elem,_Traits>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
: error C2039: 'close' : is not a member of 'std::basic_istream<_Elem,_Traits>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
*/

I mean i never this problem, and this stream has been used this way

[csonx_p]

C++ can be quite confusing for me... Haven't touched this file in weeks and it has been compiling with no probs,now today after having been growing my project by modifying other classes, i get an error from a class which hasn't been modified and has been compiling

here's part of the class

#include "Fleet.h"
#include <fstream>
#include <iostream>
#include <algorithm>
#include <conio.h>

using namespace std;

struct CAR_MAKE 
{ 
    string make; 
    string model;
};

Fleet::Fleet(): fleet() {}

Fleet::CarFleet Fleet::getFleet()
{
	return fleet;
}

// ---------------------------------------------------------------
// Implementing function to read fleet of cars from text file

void Fleet::ReadFleetFromFile()
{					
	char filename[MAX_PATH] ;

	puts("\n\nPlease enter the text file to open:\n");
	cin >> filename;

	istream fleetin; // Problem is here
	fleetin.open (filename);

	/* Ensure file was openned, otherwise send an error */
	if ( fleetin.fail() )
	{
		puts("");
		perror("ERROR! while trying to open file");
		exit(1);
	}
	else
	{
		Car car;	
		
		// Read in fleet records
		while ( !car.Read(fleetin) )
		{
			fleet.push_back(car);
			SortAlpha();		
		}
		
		// Did we read something?
		if( fleet.size()==0) {
			puts("\nData was unsuccessfully read !!...");
		}
		else
			puts("\nProcessed reading...");
	}

	fleetin.close();

}

/* ERROR 

: error C2512: 'std::basic_istream<_Elem,_Traits>' : no appropriate default constructor available
        with
        [
           _Elem=char,
           _Traits=std::char_traits<char>
        ]
: error C2039: 'open' : is not a member of 'std::basic_istream<_Elem,_Traits>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
: error C2039: 'close' : is not a member of 'std::basic_istream<_Elem,_Traits>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
*/

I mean i never this problem, and this stream has been used this way

Oh! flip, should be ifstream ...