Using a C program to create directories in UNIX

Applications Programming
1

Aloha,

I'm attempting to use a C program to create directories and then use a system call to have another program write .dat files into that directory. I understand that I could use the "system("mkdir directory_name")" function however, I would like my program to create a new directory each time the program loops by incrementing an integer contained in the file name each loop. Here are some example directory names: A1, A2, A3, A4, A5...

I know that this isn't the proper use of the system function, but below is some code that might better illustrate what im trying to do.

main()
{
int i;
for(i=0;i<5;i++)
system("mkdir A%d",i);
}

I also don't mind using a string of characters in an array that I would modify each time I pass through the loop and use as the directory's name.

Does anyone know of a simple way to have a C program create unique directories each time it passes through a loop, by incrementing an integer contained in the file name?

Mahalo,
Windell

2

You are on the right track, just have to change the syntax of system. You have to do something like this:

#include<stdio.h>
#include<stdlib.h>

int main() {
        int i;
        char command[50];
        for(i=0;i<5;i++) {
                sprintf(command,"mkdir A%d",i);
                system(command);
        }
}
3

Using system() to invoke the mkdir program is rather expensive. Why not just use the mkdir system call? It would be much faster.

4

I thought that I'd just fix the OP's code, rather than present a totally new approach. But, here goes:

#include<stdio.h>
#include<sys/stat.h>

int main() {
        int i;
        char dirname[50];

        for(i=0;i<10;i++) {
                sprintf(dirname,"A%d",i);
                if((mkdir(dirname,00777))==-1) {
                        fprintf(stdout,"error in creating dir\n");
                }
        }
}

Note: only rudimentary error checking has been implemented in above code.