/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*      factor  COMPILE:        cc -O factor.c -s -i -lm -o factor      */
/*
 * works up to 14 digit numbers
 * running time is proportional to sqrt(n)
 * accepts arguments either as input or on command line
 * 0 input terminates processing
 */

double modf(), sqrt();
double nn, vv;
double huge = 1.0e14;
double sq[] = {
        10, 2, 4, 2, 4, 6, 2, 6,
         4, 2, 4, 6, 6, 2, 6, 4,
         2, 6, 4, 6, 8, 4, 2, 4,
         2, 4, 8, 6, 4, 6, 2, 4,
         6, 2, 6, 6, 4, 2, 4, 6,
         2, 6, 4, 2, 4, 2,10, 2,
};

void try(double);

int
main(int argc, char *argv[])
{
        int test = 1;
        int ret;
        int j;
        double junk, temp;
        double fr;
        double ii;

        if(argc > 2){
                printf("Usage: factor number\n");
                exit(1);
        }
        if(argc == 2){
                ret = sscanf(argv[1], "%lf", &nn);
                test = 0;
                printf("%.0f\n", nn);
                goto start;
        }
        while(test == 1){
                ret = scanf("%lf", &nn);
start:
                if((ret<1) || (nn == 0.0)){
                        exit(0);
                }
                if((nn<0.0) || (nn>huge)){
                        printf("Ouch!\n");
                        continue;
                }
                fr = modf(nn, &junk);
                if(fr != 0.0){
                        printf("Not an integer!\n");
                        continue;
                }
                vv = 1. + sqrt(nn);
                try(2.0);
                try(3.0);
                try(5.0);
                try(7.0);
                ii = 1.0;
                while(ii <= vv){
                        for(j=0; j<48; j++){
                                ii += sq[j];
retry:
                                modf(nn/ii, &temp);
                                if(nn == temp*ii){
                                        printf("     %.0f\n", ii);
                                        nn = nn/ii;
                                        vv = 1 + sqrt(nn);
                                        goto retry;
                                }
                        }
                }
                if(nn > 1.0){
                        printf("     %.0f\n", nn);
                }
                printf("\n");
        }
        return (0);
}

void
try(double arg)
{
        double temp;
retry:
        modf(nn/arg, &temp);
        if(nn == temp*arg){
                printf("     %.0f\n", arg);
                nn = nn/arg;
                vv = 1 + sqrt(nn);
                goto retry;
        }
}