BSArch/01/prime.c

/* $Id: prime.c,v 1.10 2006/05/13 12:06:38 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)

#define MAX_LINE_LENGTH 80


/* 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 line[MAX_LINE_LENGTH + 1];
                        long int number;
                        int line_length;
                        long int line_no = 0;
                        while (fgets(line, MAX_LINE_LENGTH + 1, fp)) {
                                
                                /* count line number (for warnings) */
                                line_no++;

                                line_length = strlen(line);
                                
                                /* skip empty lines */
                                if (strlen(line) < 2) continue;

                                /* line handling: policy = skip exceeding lines */
                                
                                /* line exceeds max length */
                                if (line_length == MAX_LINE_LENGTH && line[line_length-1] != '\n') {
                                        char message[254];
                                        snprintf(message, 256, "Line too long (max %i chars) in line number: %i", MAX_LINE_LENGTH, line_no);
                                        PRINTWARNING(message);
                                        
                                        /* eat all characters until newline or EOF */
                                        while (1) {
                                                int charcode = fgetc(fp);
                                                if (charcode == 10 || charcode == EOF) break;
                                        }
                                        
                                        /* skip this line from prime calculation */
                                        continue;
                                }
                                
                                /* if last char is newline, strip it */
                                if (line[line_length-1] == '\n') {
                                        line[line_length-1] = '\0';
                                }
                                
                                /* finally: prime number calculation and output */
                                number = convert_number(line);
                                PRINTPRIME(number);
                                
                        }
                        fclose(fp);
                }
        }
}
1	/* $Id: prime.c,v 1.10 2006/05/13 12:06:38 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	#define MAX_LINE_LENGTH 80
17
18
19	/* check for prime number */
20	BOOL is_prime(long int number)
21	{
22	int i;
23
24	/* negative values, 0 and 1 are never prime numbers */
25	if (number < 2) return FALSE;
26
27	/* check all numbers 2..sqrt(number) for being a prime number */
28	for (i=2; i*i <= number; i++) {
29	if ((number % i) == 0)
30	return FALSE;
31	}
32	return TRUE;
33	}
34
35	/* convert from string to long int, with error checking */
36	long int convert_number(const char *nptr) {
37
38	char * endptr;
39	long int number = strtol(nptr, &endptr, 10);
40
41	errno = 0;
42
43	/* invalid characters? */
44	if (*endptr != '\0') {
45	char message[254];
46	snprintf(message, 256, "Could not convert '%s' to a valid number.", nptr);
47	PRINTERROR(message);
48	exit(EXIT_FAILURE);
49	}
50
51	/* invalid range? */
52	/* if (number == LONG_MAX \|\| number == LONG_MIN) { */
53	if (errno == ERANGE) {
54	char message[254];
55	snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
56	PRINTERROR(message);
57	exit(EXIT_FAILURE);
58	}
59
60	return number;
61
62	}
63
64	int main(int argc, char * argv[])
65	{
66
67	if (argc == 1) {
68	PRINTERROR("No arguments given.");
69	exit(EXIT_FAILURE);
70	}
71
72	/* (3) range mode */
73	if (argc > 2) {
74	long int i, j;
75	i = convert_number(argv[1]);
76	j = convert_number(argv[2]);
77	for (i; i< j; i++) {
78	PRINTPRIME(i);
79	}
80
81	/* other modes */
82	} else {
83
84	/* try to open file for reading */
85	FILE * fp = fopen(argv[1], "r");
86
87	/* (1) test-single-number mode: first argument is not a filename */
88	if (fp == NULL) {
89	long int number = convert_number(argv[1]);
90	PRINTPRIME(number);
91
92	/* (2) file mode: read numbers from file */
93	} else {
94	char line[MAX_LINE_LENGTH + 1];
95	long int number;
96	int line_length;
97	long int line_no = 0;
98	while (fgets(line, MAX_LINE_LENGTH + 1, fp)) {
99
100	/* count line number (for warnings) */
101	line_no++;
102
103	line_length = strlen(line);
104
105	/* skip empty lines */
106	if (strlen(line) < 2) continue;
107
108	/* line handling: policy = skip exceeding lines */
109
110	/* line exceeds max length */
111	if (line_length == MAX_LINE_LENGTH && line[line_length-1] != '\n') {
112	char message[254];
113	snprintf(message, 256, "Line too long (max %i chars) in line number: %i", MAX_LINE_LENGTH, line_no);
114	PRINTWARNING(message);
115
116	/* eat all characters until newline or EOF */
117	while (1) {
118	int charcode = fgetc(fp);
119	if (charcode == 10 \|\| charcode == EOF) break;
120	}
121
122	/* skip this line from prime calculation */
123	continue;
124	}
125
126	/* if last char is newline, strip it */
127	if (line[line_length-1] == '\n') {
128	line[line_length-1] = '\0';
129	}
130
131	/* finally: prime number calculation and output */
132	number = convert_number(line);
133	PRINTPRIME(number);
134
135	}
136	fclose(fp);
137	}
138	}
139	}
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