BSArch/01/prime.c

/* $Id: prime.c,v 1.6 2006/05/12 21:13:49 joko Exp $ */

#include <stdio.h>
#include <stdlib.h>
#include <limits.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 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) {
        long int number = strtol(nptr, (char **)NULL, 10);
        if (number == LONG_MAX || number == LONG_MIN) {
                char message[254];
                snprintf(message, 255, "Number is not in range of 'long int': %s", nptr);
                PRINTERROR(message);
                exit(-1);
        }
}

int main(int argc, char * argv[])
{
        
        if (argc == 1) {
                PRINTERROR("No arguments given.");
                exit(-1);
        }
        
        /* (3) range mode */
        if (argc > 2) {
                long int i, j;
                j = convert_number(argv[2]);
                for (i = convert_number(argv[1]); 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	/* $Id: prime.c,v 1.6 2006/05/12 21:13:49 joko Exp $ */
2
3	#include <stdio.h>
4	#include <stdlib.h>
5	#include <limits.h>
6
7	#define BOOL int
8	#define TRUE 1
9	#define FALSE 0
10
11	#define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x)
12	#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
13
14	/* check for prime number */
15	BOOL is_prime(long int number)
16	{
17	int i;
18
19	/* negative values are never prime numbers */
20	if (number < 2) return FALSE;
21
22	/* check all numbers 2..sqrt(number) for being a prime number */
23	for (i=2; i*i <= number; i++) {
24	if ((number % i) == 0)
25	return FALSE;
26	}
27	return TRUE;
28	}
29
30	/* convert from string to long int, with error checking */
31	long int convert_number(const char *nptr) {
32	long int number = strtol(nptr, (char **)NULL, 10);
33	if (number == LONG_MAX \|\| number == LONG_MIN) {
34	char message[254];
35	snprintf(message, 255, "Number is not in range of 'long int': %s", nptr);
36	PRINTERROR(message);
37	exit(-1);
38	}
39	}
40
41	int main(int argc, char * argv[])
42	{
43
44	if (argc == 1) {
45	PRINTERROR("No arguments given.");
46	exit(-1);
47	}
48
49	/* (3) range mode */
50	if (argc > 2) {
51	long int i, j;
52	j = convert_number(argv[2]);
53	for (i = convert_number(argv[1]); i< j; i++) {
54	PRINTPRIME(i);
55	}
56
57	/* other modes */
58	} else {
59
60	/* try to open file for reading */
61	FILE * fp = fopen(argv[1], "r");
62
63	/* (1) test-single-number mode: first argument is not a filename */
64	if (fp == NULL) {
65	long int number = convert_number(argv[1]);
66	PRINTPRIME(number);
67
68	/* (2) file mode: read numbers from file */
69	} else {
70	char entry[11];
71	while (fgets(entry, 11, fp)) {
72	long int number = convert_number(entry);
73	PRINTPRIME(number);
74	}
75	fclose(fp);
76	}
77	}
78	}
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