fin fout, file pointer question

Hello

I wrote a program that has a function in it that prints to an output file...

I want to use the file pointer fout

But whenever I declare fout outside of the main function... like a global variable, I get an error

and if I declare fout in main, then my function can't see it

does anyone now a way out of this problem?

this is what I have in main:

Code:

---

                FILE *fin,*fout;
                fin = fopen("cp20550.dat", "r");
                fout = fopen("cp20550.out", "w");

---

You can declare them outside of a function. You can't call fopen outside of a function. So move the two function calls inside a function of your choice.


Quzah.

There is nothing wrong with declaring the FILE pointers outside of a function:

Code:

---

FILE *fin, *fout;

void foo(void)
{
    fin = fopen(...);
    fout = fopen(...);
}

int main(void)
{
    foo();
    /* you can use fin/fout here too */
    return 0;
}

---

You can also declare the FILE pointers inside main() and then pass them to your function. You'll just need to pass pointers to the FILE pointers if you want main() to see the changes:

Code:

---

#include <stdio.h>

void open_files(FILE **fin, FILE **fout)
{
  *fin = fopen("cp20550.dat", "r");
  *fout = fopen("cp20550.out", "w");
}

int main(void)
{
  FILE *fin, *fout;

  open_files(&fin, &fout);

  fclose(fin);
  fclose(fout);

  return 0;
}

---