/[cvs]/joko/Uni/BSArch/01/prime.c
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Annotation of /joko/Uni/BSArch/01/prime.c

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Revision 1.16 - (hide annotations)
Mon May 15 11:27:10 2006 UTC (18 years, 4 months ago) by franky
Branch: MAIN
Changes since 1.15: +2 -2 lines
File MIME type: text/plain
Und nochmal richtig ;]

1 franky 1.16 /* $Id: prime.c,v 1.15 2006/05/15 11:25:40 franky Exp $ */
2 joko 1.5
3 joko 1.1 #include <stdio.h>
4 joko 1.6 #include <stdlib.h>
5 franky 1.14 #include <math.h>
6 joko 1.6 #include <limits.h>
7 joko 1.9 #include <errno.h>
8 joko 1.3
9 joko 1.13 #ifdef _MSC_VER
10     #define snprintf _snprintf
11     #endif
12    
13 joko 1.6 #define BOOL int
14     #define TRUE 1
15     #define FALSE 0
16    
17     #define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x)
18 joko 1.5 #define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
19 joko 1.10 #define PRINTWARNING(message) fprintf(stderr, "WARNING: %s\n", message)
20 joko 1.4
21 joko 1.11 #define MAX_LINE_LENGTH 80
22    
23    
24 joko 1.5 /* check for prime number */
25 joko 1.6 BOOL is_prime(long int number)
26 joko 1.1 {
27 franky 1.14 int i,sq;
28 joko 1.9 /* negative values, 0 and 1 are never prime numbers */
29 joko 1.7 if (number < 2) return FALSE;
30 franky 1.14 sq=sqrt(number);
31 joko 1.7
32     /* check all numbers 2..sqrt(number) for being a prime number */
33 franky 1.14 for (i=2; i <= sq; i++) {
34 joko 1.4 if ((number % i) == 0)
35 joko 1.6 return FALSE;
36     }
37     return TRUE;
38     }
39    
40 joko 1.7 /* convert from string to long int, with error checking */
41 franky 1.14 long int convert_number(const char *nptr, BOOL warn) {
42 joko 1.9
43     char * endptr;
44 franky 1.15 long int number;
45    
46 franky 1.16 errno = 0;
47 franky 1.15 number = strtol(nptr, &endptr, 10);
48 joko 1.9
49     /* invalid characters? */
50     if (*endptr != '\0') {
51 franky 1.14 char message[256];
52     snprintf(message, 255, "Could not convert '%s' to a valid (integer) number.", nptr);
53     if(warn)
54     PRINTWARNING(message);
55     else{
56     PRINTERROR(message);
57     exit(EXIT_FAILURE);
58     }
59 joko 1.9 }
60    
61     /* invalid range? */
62     /* if (number == LONG_MAX || number == LONG_MIN) { */
63     if (errno == ERANGE) {
64 franky 1.14 char message[256];
65     snprintf(message, 255, "Number is not in range of 'long int': %s", nptr);
66     if(warn)
67     PRINTWARNING(message);
68     else{
69     PRINTERROR(message);
70     exit(EXIT_FAILURE);
71     }
72 joko 1.4 }
73 joko 1.9
74     return number;
75    
76 joko 1.1 }
77 joko 1.3
78 joko 1.1 int main(int argc, char * argv[])
79     {
80 joko 1.4
81     if (argc == 1) {
82 joko 1.6 PRINTERROR("No arguments given.");
83 joko 1.9 exit(EXIT_FAILURE);
84 joko 1.4 }
85    
86 joko 1.5 /* (3) range mode */
87 joko 1.4 if (argc > 2) {
88 joko 1.7 long int i, j;
89 franky 1.14 i = convert_number(argv[1],FALSE);
90     j = convert_number(argv[2],FALSE);
91 joko 1.9 for (i; i< j; i++) {
92 joko 1.1 PRINTPRIME(i);
93     }
94 joko 1.4
95 joko 1.5 /* other modes */
96 joko 1.4 } else {
97 franky 1.14 int err;
98 joko 1.5 /* try to open file for reading */
99 joko 1.4 FILE * fp = fopen(argv[1], "r");
100 franky 1.14 err=errno;
101 joko 1.5 /* (1) test-single-number mode: first argument is not a filename */
102 joko 1.4 if (fp == NULL) {
103 franky 1.14 long int number = convert_number(argv[1],TRUE);
104     if(err){
105     fprintf(stderr, "%s: %s\n", argv[1], strerror(err));
106     return -1;
107     }
108 joko 1.7 PRINTPRIME(number);
109 joko 1.4
110 joko 1.5 /* (2) file mode: read numbers from file */
111 joko 1.4 } else {
112 joko 1.11 char line[MAX_LINE_LENGTH + 1];
113 joko 1.10 long int number;
114 joko 1.11 int line_length;
115     long int line_no = 0;
116     while (fgets(line, MAX_LINE_LENGTH + 1, fp)) {
117 joko 1.10
118     /* count line number (for warnings) */
119 joko 1.11 line_no++;
120 joko 1.10
121 joko 1.11 line_length = strlen(line);
122    
123 joko 1.10 /* skip empty lines */
124 joko 1.11 if (strlen(line) < 2) continue;
125 joko 1.10
126     /* line handling: policy = skip exceeding lines */
127    
128     /* line exceeds max length */
129 joko 1.11 if (line_length == MAX_LINE_LENGTH && line[line_length-1] != '\n') {
130 joko 1.10 char message[254];
131 joko 1.11 snprintf(message, 256, "Line too long (max %i chars) in line number: %i", MAX_LINE_LENGTH, line_no);
132 joko 1.10 PRINTWARNING(message);
133    
134 joko 1.11 /* eat all characters until newline or EOF */
135     while (1) {
136     int charcode = fgetc(fp);
137     if (charcode == 10 || charcode == EOF) break;
138     }
139 joko 1.10
140     /* skip this line from prime calculation */
141     continue;
142     }
143    
144 joko 1.11 /* if last char is newline, strip it */
145     if (line[line_length-1] == '\n') {
146     line[line_length-1] = '\0';
147     }
148    
149     /* finally: prime number calculation and output */
150 franky 1.14 number = convert_number(line,FALSE);
151 joko 1.7 PRINTPRIME(number);
152 joko 1.11
153 joko 1.5 }
154 joko 1.1 fclose(fp);
155     }
156     }
157     }

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