Thread: txt file from ofstream. Increment the files name?

Hi all

I'm trying to generate some text files and have the name of each file created increment or be random (doesn't matter which), but am having difficult as the way I know of creating txt files is by placing the name of the file between double quotes. I have tried replacing the name part with rand(), and also by placing a variable where the name appears and then incrementing the value of the variable on each iteration of the loop (variablename++).

Both failed.

Here is my code, pretty standard:

Code:

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

void main()
{
	for(int a =0;a<99;a++)
	{

		ofstream out("WantToIncrementThis");
		if(!out)
		{
			cout << "cannot open file";
		}
		out << rand() << rand() << rand()<< rand() << rand() << rand()<< rand() << rand() << rand();

		out.close();
	}
	system ("pause");
}

So I just wondering how I should go about this.

Many thanks for any help1!

Swerve

"Print" a string (using stringstreams, for instance), and then use string.c_str() in the ofstream constructor.

There's also tmpnam in ... cstdio, I guess.

Example:

Code:

	char Filename[256] = "File";

	for(int i = 0; i < 10; i++)
	{
		sprintf_s(Filename,"File%d",i+1);
		cout << Filename;
	}

Or if you want to be standard C...

Example:

Code:

	char Filename[256];

	for(int i = 0; i < 10; i++)
	{
		std::snrintf(Filename, sizeof(Filename), "File&#37;02d",i+1);
		std::printf("%s\n", Filename);
	}

The extra arguments I put in there are because I like my files to be listed numerically in order.

There is a more C++ approach to this using stringstreams.

Example:

Code:

#include <sstream>

//... later in your code

std::stringstream Filename;

for(int i = 0; i < 10; ++i)
{
  Filename.clear();
  Filename << "File";
  Filename.fill('0');
  Filename.width(2);
  Filename << i;
  std::cout << Filename.str().c_str() << std::endl;
}