BSArch/01/prime.c

/* $Id$ */

#include <stdio.h>

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

/* check for prime number */
int is_prime(int number)
{
        int i;
        for (i=2; i*i <= number; i++) {
                if ((number % i) == 0)
                        return 0;
        }
        return 1;
}

int main(int argc, char * argv[])
{
        
        if (argc == 1) {
                PRINTERROR("No arguments given, will segfault under cygwin. :-)");
                return -1;
        }
        
        /* (3) range mode */
        if (argc > 2) {
                int i, j;
                j = atoi(argv[2]);
                for (i = atoi(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) {
                        PRINTPRIME(atoi(argv[1]));
                
                /* (2) file mode: read numbers from file */
                } else {
                        char num[11];
                        while (fgets(num, 11, fp)) {
                                printf("raw: %s\n", num);
                                printf("num: %i\n", atoi(num));
                                PRINTPRIME(atoi(num));
                        }
                        fclose(fp);
                }
        }
}
1	/* $Id$ */
2
3	#include <stdio.h>
4
5	#define PRINTPRIME(x) if(is_prime(x)) printf("%i\n", x)
6	#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
7
8	/* check for prime number */
9	int is_prime(int number)
10	{
11	int i;
12	for (i=2; i*i <= number; i++) {
13	if ((number % i) == 0)
14	return 0;
15	}
16	return 1;
17	}
18
19	int main(int argc, char * argv[])
20	{
21
22	if (argc == 1) {
23	PRINTERROR("No arguments given, will segfault under cygwin. :-)");
24	return -1;
25	}
26
27	/* (3) range mode */
28	if (argc > 2) {
29	int i, j;
30	j = atoi(argv[2]);
31	for (i = atoi(argv[1]); i< j; i++) {
32	PRINTPRIME(i);
33	}
34
35	/* other modes */
36	} else {
37
38	/* try to open file for reading */
39	FILE * fp = fopen(argv[1], "r");
40
41	/* (1) test-single-number mode: first argument is not a filename */
42	if (fp == NULL) {
43	PRINTPRIME(atoi(argv[1]));
44
45	/* (2) file mode: read numbers from file */
46	} else {
47	char num[11];
48	while (fgets(num, 11, fp)) {
49	printf("raw: %s\n", num);
50	printf("num: %i\n", atoi(num));
51	PRINTPRIME(atoi(num));
52	}
53	fclose(fp);
54	}
55	}
56	}
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