how to pass an ifstream object to a function

hi masters!!

can anyone plese help me in this?
i want to pass an ifstream object to function.

please dont suggest me to use istream instead!!!!!!!

i know it can b passed by reference, but i am not been able to do that!!

my code

Code:

#pragma warning(disable:4786)
#pragma warning(disable:4996)

#include <vector>
#include "common.h"
#include "defFile.h"
#include<uf.h>
#include <iostream>
#include <uf_part.h>
#include <uf_curve.h>
#include"runner_blade.h"

using namespace std;
void defFile::readFile(char *DefFileName)
{ 
	char buf[256];
	int i=0,j=0;
	ifstream inpfile;
	inpfile.open(DefFileName);
	while(!inpfile.eof())
	{
		inpfile.getline(buf,256,'\n');
		if(strstr(buf,"action"))
		{
			//I'm check whether the string action is coming or not		
			inpfile.getline(buf,256,'\n');		
			sscanf(buf,"%d %d",&ActionSide.NumberOfSections,&ActionSide.NumberOfPoints);
			readLine(ActionSide.NumberOfSections,ActionSide.NumberOfPoints,ifstream &inpfile);			
		}
	}
	inpfile.close();
}

error:


1>d:\backup_qi-287\geconfidential\rajesh\hitachi_runner_blade\cod e_runner_blade\runner_blde\runner_blde\deffile.cpp (28) : error C2275: 'std::ifstream' : illegal use of this type as an expression

It sounds like you need to #include <fstream>

please dont suggest me to use istream instead!

If I suggest using an ifstream, I'm suggesting to use an istream, since an ifstream is an istream.

thanks for suggestion but still its not working & i think u misunderstood me ! i want to use "ifstream " . i dont want to use "istream"!

thanks for suggestion but still its not working

Ah, but what is the error message now? I suspect it has changed, because the next problem you have appears to be here:

Code:

readLine(ActionSide.NumberOfSections,ActionSide.NumberOfPoints,ifstream &inpfile);

If readLine() takes an ifstream (or istream, for that matter) by reference, you would write:

Code:

readLine(ActionSide.NumberOfSections, ActionSide.NumberOfPoints, inpfile);

i think u misunderstood me ! i want to use "ifstream " . i dont want to use "istream"!

I understand you very well. You, on the other hand, do not understand that there is an is-a relationship between ifstream and istream, and consequently you should prefer to use reference to istream parameters unless ifstream specific functionality is to be used.

hi expert!! i have done whatever u said & i am getting this error!! u have to b very patient with me, because i am begineer!!!

thanks!!



error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>'

error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>'

On which line is that?

i cant tell , it directly goes to fstream!!!

i cant tell , it directly goes to fstream!!! when i click on error

Take a look at your previous error message:

d:\backup_qi-287\geconfidential\rajesh\hitachi_runner_blade\cod e_runner_blade\runner_blde\runner_blde\deffile.cpp (28) : error C2275: 'std::ifstream' : illegal use of this type as an expression

See the part that I bolded? That's the line number. Look for that in your current error message.

sorry went for lunch, i am not been able to find it .i have pasted whole stack here!!










1>------ Build started: Project: runner_blde, Configuration: Debug Win32 ------
1>Compiling...
1>defFile.cpp
1>d:\apps\microsoft visual studio 8\vc\include\fstream(675) : error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1> d:\apps\microsoft visual studio 8\vc\include\ios(151) : see declaration of 'std::basic_ios<_Elem,_Traits>::basic_ios'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1> This diagnostic occurred in the compiler generated function 'std::basic_ifstream<_Elem,_Traits>::basic_ifstrea m(const std::basic_ifstream<_Elem,_Traits> &)'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1>Build log was saved at "file://d:\Backup_QI-287\GEConfidential\rajesh\Hitachi_runner_blade\cod e_runner_blade\runner_blde\runner_blde\Debug\Build Log.htm"
1>runner_blde - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Streams are non-copiable and their copy constructors are private for that reason.

Are you trying to pass a stream to a function by value? You can't do that and must pass a reference.

hi anon,

i tried passing it with reference but it is giving below error,


d:\backup_qi-287\geconfidential\rajesh\hitachi_runner_blade\cod e_runner_blade\runner_blde\runner_blde\deffile.cpp (28) : error C2275: 'std::ifstream' : illegal use of this type as an expression

The code in the first post?

Whether something is passed by reference or by value is determined where the function is declared/defined, not where it is called.

Example of a function that takes a reference.

Code:

void foo(std::istream& is); //declaration

//implementation
void foo(std::istream& is) 
{
}

anon i dont want to use istream !! i am using ifstream!!!after declaring as u said i get this error!

error C2275: 'std::ifstream' : illegal use of this type as an expression

thanks got it!!!!!!!!!!!!!!!