BSArch/01/prime.c

/* $Id: prime.c,v 1.9 2006/05/13 09:20:36 joko Exp $ */

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>

#define BOOL int
#define TRUE 1
#define FALSE 0

#define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x)
#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
#define PRINTWARNING(message) fprintf(stderr, "WARNING: %s\n", message)

/* check for prime number */
BOOL is_prime(long int number)
{
        int i;
        
        /* negative values, 0 and 1 are never prime numbers */
        if (number < 2) return FALSE;
        
        /* check all numbers 2..sqrt(number) for being a prime number */
        for (i=2; i*i <= number; i++) {
                if ((number % i) == 0)
                        return FALSE;
        }
        return TRUE;
}

/* convert from string to long int, with error checking */
long int convert_number(const char *nptr) {
        
        char * endptr;
        long int number = strtol(nptr, &endptr, 10);

        errno = 0;
        
        /* invalid characters? */
        if (*endptr != '\0') {
                char message[254];
                snprintf(message, 256, "Could not convert '%s' to a valid number.", nptr);
                PRINTERROR(message);
                exit(EXIT_FAILURE);
        }
        
        /* invalid range? */
        /* if (number == LONG_MAX || number == LONG_MIN) { */
        if (errno == ERANGE) {
                char message[254];
                snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
                PRINTERROR(message);
                exit(EXIT_FAILURE);
        }
        
        return number;
        
}

int main(int argc, char * argv[])
{
        
        if (argc == 1) {
                PRINTERROR("No arguments given.");
                exit(EXIT_FAILURE);
        }
        
        /* (3) range mode */
        if (argc > 2) {
                long int i, j;
                i = convert_number(argv[1]);
                j = convert_number(argv[2]);
                for (i; i< j; i++) {
                        PRINTPRIME(i);
                }
        
        /* other modes */
        } else {

                /* try to open file for reading */
                FILE * fp = fopen(argv[1], "r");
                
                /* (1) test-single-number mode: first argument is not a filename */
                if (fp == NULL) {
                        long int number = convert_number(argv[1]);
                        PRINTPRIME(number);
                
                /* (2) file mode: read numbers from file */
                } else {
                        char entry[81];
                        long int number;
                        long int lineno = 0;
                        while (fgets(entry, 81, fp)) {
                                
                                /* count line number (for warnings) */
                                lineno++;

                                /* skip empty lines */
                                if (strlen(entry) < 2) continue;

                                /* line handling: policy = skip exceeding lines */
                                
                                /* if last char is newline, strip it */
                                if (entry[strlen(entry)-1] == '\n') {
                                        entry[strlen(entry)-1] = '\0';
                                        
                                /* line exceeds max length */
                                } else {
                                        char message[254];
                                        snprintf(message, 256, "Line too long (max 80 chars) in line number: %i", lineno);
                                        PRINTWARNING(message);
                                        
                                        /* eat all characters until newline */
                                        while (fgetc(fp) != 10);
                                        
                                        /* skip this line from prime calculation */
                                        continue;
                                }
                                
                                number = convert_number(entry);
                                PRINTPRIME(number);
                        }
                        fclose(fp);
                }
        }
}
1	/* $Id: prime.c,v 1.9 2006/05/13 09:20:36 joko Exp $ */
2
3	#include <stdio.h>
4	#include <stdlib.h>
5	#include <limits.h>
6	#include <errno.h>
7
8	#define BOOL int
9	#define TRUE 1
10	#define FALSE 0
11
12	#define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x)
13	#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
14	#define PRINTWARNING(message) fprintf(stderr, "WARNING: %s\n", message)
15
16	/* check for prime number */
17	BOOL is_prime(long int number)
18	{
19	int i;
20
21	/* negative values, 0 and 1 are never prime numbers */
22	if (number < 2) return FALSE;
23
24	/* check all numbers 2..sqrt(number) for being a prime number */
25	for (i=2; i*i <= number; i++) {
26	if ((number % i) == 0)
27	return FALSE;
28	}
29	return TRUE;
30	}
31
32	/* convert from string to long int, with error checking */
33	long int convert_number(const char *nptr) {
34
35	char * endptr;
36	long int number = strtol(nptr, &endptr, 10);
37
38	errno = 0;
39
40	/* invalid characters? */
41	if (*endptr != '\0') {
42	char message[254];
43	snprintf(message, 256, "Could not convert '%s' to a valid number.", nptr);
44	PRINTERROR(message);
45	exit(EXIT_FAILURE);
46	}
47
48	/* invalid range? */
49	/* if (number == LONG_MAX \|\| number == LONG_MIN) { */
50	if (errno == ERANGE) {
51	char message[254];
52	snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
53	PRINTERROR(message);
54	exit(EXIT_FAILURE);
55	}
56
57	return number;
58
59	}
60
61	int main(int argc, char * argv[])
62	{
63
64	if (argc == 1) {
65	PRINTERROR("No arguments given.");
66	exit(EXIT_FAILURE);
67	}
68
69	/* (3) range mode */
70	if (argc > 2) {
71	long int i, j;
72	i = convert_number(argv[1]);
73	j = convert_number(argv[2]);
74	for (i; i< j; i++) {
75	PRINTPRIME(i);
76	}
77
78	/* other modes */
79	} else {
80
81	/* try to open file for reading */
82	FILE * fp = fopen(argv[1], "r");
83
84	/* (1) test-single-number mode: first argument is not a filename */
85	if (fp == NULL) {
86	long int number = convert_number(argv[1]);
87	PRINTPRIME(number);
88
89	/* (2) file mode: read numbers from file */
90	} else {
91	char entry[81];
92	long int number;
93	long int lineno = 0;
94	while (fgets(entry, 81, fp)) {
95
96	/* count line number (for warnings) */
97	lineno++;
98
99	/* skip empty lines */
100	if (strlen(entry) < 2) continue;
101
102	/* line handling: policy = skip exceeding lines */
103
104	/* if last char is newline, strip it */
105	if (entry[strlen(entry)-1] == '\n') {
106	entry[strlen(entry)-1] = '\0';
107
108	/* line exceeds max length */
109	} else {
110	char message[254];
111	snprintf(message, 256, "Line too long (max 80 chars) in line number: %i", lineno);
112	PRINTWARNING(message);
113
114	/* eat all characters until newline */
115	while (fgetc(fp) != 10);
116
117	/* skip this line from prime calculation */
118	continue;
119	}
120
121	number = convert_number(entry);
122	PRINTPRIME(number);
123	}
124	fclose(fp);
125	}
126	}
127	}
MailToCvsAdmin">MailToCvsAdmin	ViewVC Help
Powered by ViewVC 1.1.26