ASCII ENCODER

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

#define NL printf ("\n")

int code (char filename [], char newfilename[], int n);
void input (char filename [], char newfilename[], int n);

int main (void)
{
    int n=0;
    char filename [80];
    char newfilename [80];

    input (filename, newfilename,n);

    code (filename, newfilename, n);




    return 0;
}
void input (char filename [], char newfilename[], int n)
{
    printf ("Code your file!");
    NL;
    NL;

    printf ("Dateiname: ");
    gets (filename);
    NL;

    printf ("Neuer Name: ");
    gets (newfilename);

    NL;

    printf ("Durch was soll es erstezt werden?");
    scanf ("%d",&n);

}

int code (char filename [], char newfilename[], int n)
{
    FILE *fp;
    FILE *fpnew;
    char gff;
    int buffer=0;

    if ((fp=fopen (("%s",filename),"r")) == NULL)
    {

        return -1;
    }

    if ((fpnew=fopen (("%s",newfilename),"w")) == NULL)
    {
        return -1;
    }

    do
    {
        gff=fgetc (fp);
        if (gff == EOF)
        {
            break;
        }
        buffer = atoi (&gff);
        buffer=buffer+n;
        fprintf (fpnew,"%d",buffer);


    }while (gff != EOF);






}