input file

[juanf0503]

Hi guys I am writing a C++ program on Linux that will be able to open and gather certain info from a set of files located on a file on my home directory. This file is named dmf.out Now all this file contains is the paths to these files or file names. For example: /home/int/sstf/int_02JA_006/target/ssf_host/datastores_1/02JA/datastore files and so on..... Now the program I have written so far does manage to open the first file in dmf.out and gather the required info I want from the first file. The problem is that the second file or the next one in line will not open. Therefore when I run my program (string info) repeats and repeats to be outputted. In my source code below I made a seperate file (dmf2.out) that only contains two files so that I can test this program.

#include <iostream>
#include <fstream>
#include <string>
#include <ctring> //dont't know if I need this

using namespace std;

int main ()
{

ifstream inData;
ifstream inDmf;
string file, dmf, info;
int counter=0;
inData.open("dmf2.out");
inData>>file //prime in read

while (inData)
{
inDmf.open(file.c_str()); /*this is the problem I think the value of file will not change here*/
while (inDmf)
{
getline (inDmf, dmf, '~'); // reads the file as a whole string
info= dmf.substr(0,dmf.find("SSF_HOST"));/* only pulls out certain info up to "SSF_HOST" inside of contents */
}

inDmf.close();
cout<<info<<endl; //outputs the info I want
cout<<file<<endl // file here is still the first file from dmf2.out
counter++; //counts how many files are in dmf2.out
inData>>file;
cout<<file<<endl; // file here is the second file from dmf2.out
}
cout<<counter<<endl; /*outputs a value of 2 becuase dmf2.out only contains 2 files */


return 0;
}


Output: these 7 things

1. the string info-which is the information I wanted from the file contained in dmf2.out

2.the string file- which here is still the first file from dmf2.out
3. the string file-(after it has gone through the command inData>>file) -which is now the second file of dmf2.out.
4. the string info-same as above ^^^^^^
5. the string file - which is still the second file of dmf2.out,
6. the string file - same as above^^^^^^^
7. int counter - which a 2 is outputted

I think the "inDmf.open(file.c_str());" command will not use the new file after file has under gone the command "inData>>file". I have looked up the command c_str(); in the library and maybe the reason it does not work is you can not modify the file.c_str() command once it has been executed. Any adivce or help would be highly appreciated becuase I have spent nearly the whole day looking for another way or command how to do it. THANK YOU VERY MUCH FOR READING THIS!!

[kbw]

You're file object is declared at the wrong scope:

int main ()
{
	string info;
	int counter=0;

	ifstream inData("dmf2.out");
	while (inData)
	{
		string file;
		inData>>file //prime in read
		ifstream inDmf(file.c_str());
		while (inDmf)
		{
			string dmf;
			getline(inDmf, dmf, '~'); // reads the file as a whole string
			info = dmf.substr(0,dmf.find("SSF_HOST"));/* only pulls out certain info up to "SSF_HOST" inside of contents */
		}

		inDmf.close();
		cout<<info<<endl; //outputs the info I want
		cout<<file<<endl // file here is still the first file from dmf2.out
		counter++; //counts how many files are in dmf2.out
		inData>>file;
		cout<<file<<endl; // file here is the second file from dmf2.out
	}
	cout<<counter<<endl; /*outputs a value of 2 becuase dmf2.out only contains 2 files */

	return 0;
}

[juanf0503]

Thank you very much for you reccomendation. I tried your method and the only ouput i got was the string file changing as it undergoes (inData>>file). So there was no string info output at all. I mean there was but for some reason it was just a blank line. I tried changing the argument in the while loops to while(! inData.eof() ) while(! inDmf.eof() ) This method got me the output of:
1. the string info but only for the first entry in "dmf2.out"
2. the string file twice as mentioned above ^^^
3. I got no ouput of int counter

I highly apprecitae the help and there has to be another way of reading the the files inside of "dmf2.out". I still think the call "file.c_str()" will not change and there has to be another way for ifstream to read it. If there is any other method or way you can reccomend I would be of much help to me.

[kbw]

Instead of:
inData>>file //prime in read

it's customary to read the whole line with:
std::getline(inData, file); //prime in read

The former reads up to the first white space.