concatenate files using CAT function in C

#include 

main(argc, argv)        /* cat: concatenate files */
int argc;
char *argv[];
{
    FILE *fp, *fopen();

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

filecopy(fp)    /* copy file fp to standard output */
FILE *fp;
{
    int c;

    while ((c = getc(fp)) != EOF)
        putc(c, stdout);
}