#include <stdio.h>

/* cat:  concatenate files, version 2 */
main(int argc, char *argv[])
{
    FILE *fp;
    void filecopy(FILE *, FILE *);
    char *prog = argv[0];   /* program name for errors */

    if (argc == 1)  /* no args; copy standard input */
        filecopy(stdin, stdout);
    else
        while (--argc > 0)
            if ((fp = fopen(*++argv, "r")) == NULL) {
                fprintf(stderr, "%s: can't open %s\n",
                    prog, *argv);
                exit(1);
            } else {
                filecopy(fp, stdout);
                fclose(fp);
            }
    if (ferror(stdout)) {
        fprintf(stderr, "%s: error writing stdout\n", prog);
        exit(2);
    }
    exit(0);
}