/* File: filecopy.c
 *
 * An example that uses files and command line arguments.
 * Takes two filenames as command line arguments, and copies the contents
 * of the first file to the second.
 *
 * Because the '\n' and the '\0' are included in the strings returned by
 * fgets, any input line longer than 78 characters will be terminated.
 */

#include <stdio.h>

#define MAXLINE      80                  /* max length of string */

int main(int argc, char *argv[])
{
    FILE *fpin, *fpout;                  /* pointers to in&out files */
    char line[MAXLINE];                  /* buffer to hold data */

    if (argc < 3)                        /* must be 3 arguments - command */
    {                                    /*   plus 2 filenames            */
        fprintf(stderr, "Usage: %s from_file to_file\n", argv[0]);
        return 0;
    }
                                         /* open the first file readonly */
    if ((fpin  = fopen(argv[1], "r")) == NULL)
    {
        fprintf(stderr, "Error opening file %s\n", argv[1]);
        return 0;
    }
                                         /* open the 2nd file writeonly */
    if ((fpout = fopen(argv[2], "w")) == NULL)
    {
        fprintf(stderr, "Error opening file %s\n", argv[2]);
        fclose(fpin);                    /* better close the 1st file */
        return 0;
    }
                                         /* loop through the first file */
    while (fgets(line, MAXLINE, fpin))   /*  copying each line to the 2nd */
        if (fputs(line, fpout) < 0)
        {
            fprintf(stderr, "Error writing to %s\n", argv[2]);
            break;
        }

    fclose(fpin);                        /* close the files */
    fclose(fpout);
    return 0;
}