DaniWeb Forum Index > Software Development > C++

C++ RSS

Input file data

Please support our C++ advertiser: Intel Parallel Studio Home

Thread Solved

•

Join Date: Apr 2008

Posts: 160

Reputation: dmanw100 is on a distinguished road

Solved Threads: 12

dmanw100

Offline

Junior Poster

Input file data

Sep 1st, 2008

I was wondering if anyone was familiar with reading data from a file into your program. I tried using the file stream the same way cout is used but it doesnt seem to work properly. Would the getline(); function work? If so, how would that be implemented?

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <fstream>
#include <strings>
using namespace std;
 
int main()
{
    fstream readFile;
    readFile.open("Input.txt");
    string sample;
    readfile<<sample;
    cout<<"Here is a line: "<<sample;
    return 0;
#include <iostream>
#include <fstream>
#include <strings>
using namespace std;

int main()
{
    fstream readFile;
    readFile.open("Input.txt");
    string sample;
    readfile<<sample;
    cout<<"Here is a line: "<<sample;
    return 0;

•

Join Date: Aug 2008

Posts: 77

Reputation: mahlerfive is an unknown quantity at this point

Solved Threads: 16

mahlerfive mahlerfive is offline

Offline

Junior Poster in Training

Re: Input file data

Sep 1st, 2008

It should be

Help with Code Tags

C++ Syntax (Toggle Plain Text)

readfile >> sample;

since you are getting input, not outputting.

•

Join Date: Jun 2008

Posts: 89

Reputation: raul15791 is an unknown quantity at this point

Solved Threads: 7

raul15791

Offline

Junior Poster in Training

Re: Input file data

Sep 2nd, 2008

Well.... If you want to use the getline function, here's a simple program to test that:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
 
int main()
{
	int line_number = 1;
	string line;
	ifstream myfile("test.txt");
 
	if(myfile.is_open())
	{
		while (!myfile.eof())
		{
			getline(myfile, line);
			cout << "line " << line_number << " --> " << line << endl;
			line_number++;
		}
	}
 
	else
	{
		cout << "The file cannot be opened!!" << endl;
	}
 
	system("PAUSE");
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main()
{
	int line_number = 1;
	string line;
	ifstream myfile("test.txt");

	if(myfile.is_open())
	{
		while (!myfile.eof())
		{
			getline(myfile, line);
			cout << "line " << line_number << " --> " << line << endl;
			line_number++;
		}
	}

	else
	{
		cout << "The file cannot be opened!!" << endl;
	}

	system("PAUSE");
}

•

Join Date: Dec 2005

Posts: 5,850

Reputation: Salem has a reputation beyond repute

Solved Threads: 749

Salem

Offline

Void main'ers are DOOMed

Re: Input file data

Sep 2nd, 2008

> while (!myfile.eof())
http://faq.cprogramming.com/cgi-bin/...&id=1043284351

Use
while ( getline(myfile, line) )
Try it with a small text file (say 5 lines) and note the difference.