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	joko	1.10	/* $Id: prime.c,v 1.9 2006/05/13 09:20:36 joko Exp $ */
2	joko	1.5
3	joko	1.1	#include <stdio.h>
4	joko	1.6	#include <stdlib.h>
5			#include <limits.h>
6	joko	1.9	#include <errno.h>
7	joko	1.3
8	joko	1.6	#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	joko	1.5	#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
14	joko	1.10	#define PRINTWARNING(message) fprintf(stderr, "WARNING: %s\n", message)
15	joko	1.4
16	joko	1.5	/* check for prime number */
17	joko	1.6	BOOL is_prime(long int number)
18	joko	1.1	{
19	joko	1.4	int i;
20	joko	1.7
21	joko	1.9	/* negative values, 0 and 1 are never prime numbers */
22	joko	1.7	if (number < 2) return FALSE;
23
24			/* check all numbers 2..sqrt(number) for being a prime number */
25	joko	1.4	for (i=2; i*i <= number; i++) {
26			if ((number % i) == 0)
27	joko	1.6	return FALSE;
28			}
29			return TRUE;
30			}
31
32	joko	1.7	/* convert from string to long int, with error checking */
33	joko	1.6	long int convert_number(const char *nptr) {
34	joko	1.9
35			char * endptr;
36			long int number = strtol(nptr, &endptr, 10);
37	joko	1.10
38			errno = 0;
39	joko	1.9
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	joko	1.7	char message[254];
52	joko	1.8	snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
53	joko	1.7	PRINTERROR(message);
54	joko	1.9	exit(EXIT_FAILURE);
55	joko	1.4	}
56	joko	1.9
57			return number;
58
59	joko	1.1	}
60	joko	1.3
61	joko	1.1	int main(int argc, char * argv[])
62			{
63	joko	1.4
64			if (argc == 1) {
65	joko	1.6	PRINTERROR("No arguments given.");
66	joko	1.9	exit(EXIT_FAILURE);
67	joko	1.4	}
68
69	joko	1.5	/* (3) range mode */
70	joko	1.4	if (argc > 2) {
71	joko	1.7	long int i, j;
72	joko	1.9	i = convert_number(argv[1]);
73	joko	1.7	j = convert_number(argv[2]);
74	joko	1.9	for (i; i< j; i++) {
75	joko	1.1	PRINTPRIME(i);
76			}
77	joko	1.4
78	joko	1.5	/* other modes */
79	joko	1.4	} else {
80
81	joko	1.5	/* try to open file for reading */
82	joko	1.4	FILE * fp = fopen(argv[1], "r");
83
84	joko	1.5	/* (1) test-single-number mode: first argument is not a filename */
85	joko	1.4	if (fp == NULL) {
86	joko	1.7	long int number = convert_number(argv[1]);
87			PRINTPRIME(number);
88	joko	1.4
89	joko	1.5	/* (2) file mode: read numbers from file */
90	joko	1.4	} else {
91	joko	1.10	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	joko	1.7	PRINTPRIME(number);
123	joko	1.5	}
124	joko	1.1	fclose(fp);
125			}
126			}
127			}
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