goto Statements

Can lead to spaghetti code

Not supported in Java

Used to exit after an error:

        for (;;) {
                i = 0;
                while (*cp >= '0' && *cp <= '9')
                        i = i * 10 + *cp++ - '0';
                if (i <= 0 || i > 256) {
bad:
                        fprintf(stderr, "Bad tab stop spec\n");
                        exit(1);
                }
                if (nstops > 0 && i <= tabstops[nstops-1])
                        goto bad;
                tabstops[nstops++] = i;
                if (*cp == 0)
                        break;
                if (*cp != ',' && *cp != ' ')
                        goto bad;
                cp++;
        }

Execute code again:

struct servent *
getservent()
{
        char *p;
        register char *cp, **q;

        if (servf == NULL && (servf = fopen(_PATH_SERVICES, "r" )) == NULL)
                return (NULL);
again:
        if ((p = fgets(line, BUFSIZ, servf)) == NULL)
                return (NULL);
        if (*p == '#')
                goto again;
        cp = strpbrk(p, "#\n");
        if (cp == NULL)
                goto again;
        *cp = '\0';
        serv.s_name = p;
        p = strpbrk(p, " \t");
        if (p == NULL)
                goto again;
        *p++ = '\0';
        while (*p == ' ' || *p == '\t')
                p++;
        cp = strpbrk(p, ",/");

Exit from deep control structures (instead of break):

        for (;;) {
                /* [...] */
                /* Gather incoming message bytes if needed. */
                if ((sc->sc_state & NCR_DROP_MSGIN) == 0) {
                        if (n >= NCR_MAX_MSG_LEN) {
                                ncr_sched_msgout(sc, SEND_REJECT);
                                sc->sc_state |= NCR_DROP_MSGIN;
                        } else {
                                *sc->sc_imp++ = *sc->sci_data;
                                n++;
                                /*
                                 * This testing is suboptimal, but most
                                 * messages will be of the one byte variety, so
                                 * it should not affect performance
                                 * significantly.
                                 */
                                if (n == 1 && IS1BYTEMSG(sc->sc_imess[0]))
                                        goto have_msg;
                                if (n == 2 && IS2BYTEMSG(sc->sc_imess[0]))
                                        goto have_msg;
                                if (n >= 3 && ISEXTMSG(sc->sc_imess[0]) &&
                                        n == sc->sc_imess[1] + 2)
                                        goto have_msg;
                        }
                }
                /* [...] */

                /* back to nextbyte */
        }

have_msg:
        /* We now have a complete message.  Parse it. */