BSArch/01/prime.c

/* $Id: prime.c,v 1.8 2006/05/12 23:38:15 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)

/* 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) {
        
        errno = 0;
        char * endptr;
        long int number = strtol(nptr, &endptr, 10);
        
        /* 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[11];
                        while (fgets(entry, 11, fp)) {
                                long int number = convert_number(entry);
                                PRINTPRIME(number);
                        }
                        fclose(fp);
                }
        }
}
1	joko	1.9	/* $Id: prime.c,v 1.8 2006/05/12 23:38:15 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	1.4
15	joko	1.5	/* check for prime number */
16	joko	1.6	BOOL is_prime(long int number)
17	joko	1.1	{
18	joko	1.4	int i;
19	joko	1.7
20	joko	1.9	/* negative values, 0 and 1 are never prime numbers */
21	joko	1.7	if (number < 2) return FALSE;
22
23			/* check all numbers 2..sqrt(number) for being a prime number */
24	joko	1.4	for (i=2; i*i <= number; i++) {
25			if ((number % i) == 0)
26	joko	1.6	return FALSE;
27			}
28			return TRUE;
29			}
30
31	joko	1.7	/* convert from string to long int, with error checking */
32	joko	1.6	long int convert_number(const char *nptr) {
33	joko	1.9
34			errno = 0;
35			char * endptr;
36			long int number = strtol(nptr, &endptr, 10);
37
38			/* invalid characters? */
39			if (*endptr != '\0') {
40			char message[254];
41			snprintf(message, 256, "Could not convert '%s' to a valid number.", nptr);
42			PRINTERROR(message);
43			exit(EXIT_FAILURE);
44			}
45
46			/* invalid range? */
47			/* if (number == LONG_MAX \|\| number == LONG_MIN) { */
48			if (errno == ERANGE) {
49	joko	1.7	char message[254];
50	joko	1.8	snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
51	joko	1.7	PRINTERROR(message);
52	joko	1.9	exit(EXIT_FAILURE);
53	joko	1.4	}
54	joko	1.9
55			return number;
56
57	joko	1.1	}
58	joko	1.3
59	joko	1.1	int main(int argc, char * argv[])
60			{
61	joko	1.4
62			if (argc == 1) {
63	joko	1.6	PRINTERROR("No arguments given.");
64	joko	1.9	exit(EXIT_FAILURE);
65	joko	1.4	}
66
67	joko	1.5	/* (3) range mode */
68	joko	1.4	if (argc > 2) {
69	joko	1.7	long int i, j;
70	joko	1.9	i = convert_number(argv[1]);
71	joko	1.7	j = convert_number(argv[2]);
72	joko	1.9	for (i; i< j; i++) {
73	joko	1.1	PRINTPRIME(i);
74			}
75	joko	1.4
76	joko	1.5	/* other modes */
77	joko	1.4	} else {
78
79	joko	1.5	/* try to open file for reading */
80	joko	1.4	FILE * fp = fopen(argv[1], "r");
81
82	joko	1.5	/* (1) test-single-number mode: first argument is not a filename */
83	joko	1.4	if (fp == NULL) {
84	joko	1.7	long int number = convert_number(argv[1]);
85			PRINTPRIME(number);
86	joko	1.4
87	joko	1.5	/* (2) file mode: read numbers from file */
88	joko	1.4	} else {
89	joko	1.7	char entry[11];
90			while (fgets(entry, 11, fp)) {
91			long int number = convert_number(entry);
92			PRINTPRIME(number);
93	joko	1.5	}
94	joko	1.1	fclose(fp);
95			}
96			}
97			}
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