Thread: File I/O, integers in the file name

I want to read a file, change the data and create say 50 new files from the original file, all numbereder 1 to 50.

So let's say that the original file is called "file.txt" then I want the others to be named "file1.txt" to "file50.txt". The number will be int x and I will have a loop until x > 50. The number may change.

How do I do this? I figured out how to use a string variable as a filename. I tried to see how I can create a new string out of a string and a integer but I can't figure out how to do that.

Oh, I am currently using iostream.

Thanks.

Code:

#include <iostream>
#include <string>
#include <algorithm>
#include <sstream>

using namespace std;


int main ()
{
	ostringstream out;
	
	string str = "file";
	int num = 1;
	
	out<<str<<num<<".txt";

	cout<<out.str()<<endl;

	return 0;
}

vart's code added the filenames together. Each time through the loop the name of the file became longer. First file is called "offspring1.txt", the second "offspring1.txtoffspring2.txt" etc.


Now maybe I am stupid but I couldn't figure out a way to clear the string each time through the loop. So I switched to 7stud. That gave an error. So I added a buffer like vart's code has:

Code:

string offspring_file_name;
ostringstream buffer;
     
buffer<<"offspring"<<z<<".txt";
     
offspring_file_name = buffer.str();
     
     
offspring_file.open (offspring_file_name.c_str());

This seems to work.