Thread: creating a new file but with automatically generated names

hi guys, its me again!!

i managed to create a file with a name of "1.txt"

what i want is to add 10 digits(which i can do), close the file and open a new one, do the same and so on.

up to a max of of 23 files.

the names of the files must be sequentially rising i.e.

1.txt
2.txt
3.txt
........
23.txt


this is the code, i have so far

Code:

#include <stdio.h>


#define MAX 10

int main()
{
    FILE *f;
    int x;
    f=fopen("out.txt","w");
		if fopen="out.txt"
		f=fopen("out1.txt","w");	
    if (!f)
        return 1;
    for(x=1; x<=MAX; x++)
        fprintf(f,"%d\n",x);
    fclose(f);
    return 0;
}

could anyone give me a hint!?

thanks

Make a loop. In the loop, do the following each iteration:

- Put together a file name, consisting of an index number( 1, 2, 3, etc...) and the type.
- Create the file, open it, write to it, and close it.

Theres got to be an easier way than this!!!

Code:

#include <stdio.h>


#define MAX 10

int main()
{
    FILE *f;
    int x;
    f=fopen("1.txt","w");
	if (!f)
        return 1;
    for(x=1; x<=MAX; x++)
        fprintf(f,"%d\n",x);
    fclose(f);
 
	FILE *g;
    int y;
    f=fopen("2.txt","w");
	if (!f)
        return 1;
    for(y=1; y<=MAX; y++)
        fprintf(f,"%d\n",y);
    fclose(f);
    return 0;
}

thanks sean

now, what if i wanted to add external data into each file. and had to wait until that file was completed before moving on.

i would know if the file is completed, i have already done the flags for that.

There is. You haven't implemented what I said in my previous post. You're not putting together any filenames - you're just giving them to the program. Have a number that increase each time (though you'll want to use the ASCII value of the character "1", then add 1 to get the character "2"). Concatenate the file extension to this character and use that string as your filename. Open it, write to it, close it, and then the loop should start again, incrementing the number. I'm not going to write the code for you.

now, what if i wanted to add external data into each file. and had to wait until that file was completed before moving on.

What external data is this? Unless you're using multiple threads in your program (and you're not, from what I can see) then your program won't move onto the next line until the current one is finished.

what i need to do, which i should have explained is to get data from a com port and put it into files. every preamble has a character # so i can easily recognise when to open a new file and start writing.

thats what i wanted to do.

the previous code was my own attempt at it

Originally Posted by mitakeet

untested code:

Code:

char buf[BUFSIZ];
FILE *fp;
int i, j;

for (i=0; i<MAX; i++){
    sprintf(buf, "%d.out", i+1);
    if ((fp = fopen(buf, "w")) == NULL){
        fprintf(stderr, "Can't open %s!\n", buf);
        continue;
    }
    for (j=0; j<MAX; j++)
        fprintf(fp, "%d", j);
    fclose(fp);
}

tried that code but get some errors, looking into it now.

error:

Code:

--------------------Configuration: simple file opening - Win32 Debug--------------------
Linking...
testcrap.obj : error LNK2005: _main already defined in simple file opening.obj
Debug/simple file opening.exe : fatal error LNK1169: one or more multiply defined symbols found
Error executing link.exe.

simple file opening.exe - 2 error(s), 0 warning(s)

Originally Posted by mitakeet

You are linking two files that have a main() routine. Start a new project.

thanks alot guys.

you both are stars!!