1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 /* factor COMPILE: cc -O factor.c -s -i -lm -o factor */ 31 /* 32 * works up to 14 digit numbers 33 * running time is proportional to sqrt(n) 34 * accepts arguments either as input or on command line 35 * 0 input terminates processing 36 */ 37 38 double modf(), sqrt(); 39 double nn, vv; 40 double huge = 1.0e14; 41 double sq[] = { 42 10, 2, 4, 2, 4, 6, 2, 6, 43 4, 2, 4, 6, 6, 2, 6, 4, 44 2, 6, 4, 6, 8, 4, 2, 4, 45 2, 4, 8, 6, 4, 6, 2, 4, 46 6, 2, 6, 6, 4, 2, 4, 6, 47 2, 6, 4, 2, 4, 2,10, 2, 48 }; 49 50 void try(double); 51 52 int 53 main(int argc, char *argv[]) 54 { 55 int test = 1; 56 int ret; 57 int j; 58 double junk, temp; 59 double fr; 60 double ii; 61 62 if(argc > 2){ 63 printf("Usage: factor number\n"); 64 exit(1); 65 } 66 if(argc == 2){ 67 ret = sscanf(argv[1], "%lf", &nn); 68 test = 0; 69 printf("%.0f\n", nn); 70 goto start; 71 } 72 while(test == 1){ 73 ret = scanf("%lf", &nn); 74 start: 75 if((ret<1) || (nn == 0.0)){ 76 exit(0); 77 } 78 if((nn<0.0) || (nn>huge)){ 79 printf("Ouch!\n"); 80 continue; 81 } 82 fr = modf(nn, &junk); 83 if(fr != 0.0){ 84 printf("Not an integer!\n"); 85 continue; 86 } 87 vv = 1. + sqrt(nn); 88 try(2.0); 89 try(3.0); 90 try(5.0); 91 try(7.0); 92 ii = 1.0; 93 while(ii <= vv){ 94 for(j=0; j<48; j++){ 95 ii += sq[j]; 96 retry: 97 modf(nn/ii, &temp); 98 if(nn == temp*ii){ 99 printf(" %.0f\n", ii); 100 nn = nn/ii; 101 vv = 1 + sqrt(nn); 102 goto retry; 103 } 104 } 105 } 106 if(nn > 1.0){ 107 printf(" %.0f\n", nn); 108 } 109 printf("\n"); 110 } 111 return (0); 112 } 113 114 void 115 try(double arg) 116 { 117 double temp; 118 retry: 119 modf(nn/arg, &temp); 120 if(nn == temp*arg){ 121 printf(" %.0f\n", arg); 122 nn = nn/arg; 123 vv = 1 + sqrt(nn); 124 goto retry; 125 } 126 } 127