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/* $Id$ */ |
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#include <stdio.h> |
#include <stdio.h> |
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#include <stdlib.h> |
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#include <limits.h> |
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#define BOOL int |
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#define TRUE 1 |
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#define FALSE 0 |
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#define PRINTPRIME(x) if(is_prime(x)) printf("%i\n", x) |
#define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x) |
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#define PRINTERROR(message) printf("ERROR: %s\n", message) |
#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message) |
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// check for prime number |
/* check for prime number */ |
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int is_prime(int number) |
BOOL is_prime(long int number) |
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{ |
{ |
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int i; |
int i; |
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/* negative values are never prime numbers */ |
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if (number < 2) return FALSE; |
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/* check all numbers 2..sqrt(number) for being a prime number */ |
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for (i=2; i*i <= number; i++) { |
for (i=2; i*i <= number; i++) { |
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if ((number % i) == 0) |
if ((number % i) == 0) |
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return 0; |
return FALSE; |
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} |
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return TRUE; |
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} |
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/* convert from string to long int, with error checking */ |
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long int convert_number(const char *nptr) { |
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long int number = strtol(nptr, (char **)NULL, 10); |
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if (number == LONG_MAX || number == LONG_MIN) { |
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char message[254]; |
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snprintf(message, 256, "Number is not in range of 'long int': %s", nptr); |
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PRINTERROR(message); |
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exit(-1); |
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} |
} |
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return 1; |
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} |
} |
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int main(int argc, char * argv[]) |
int main(int argc, char * argv[]) |
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{ |
{ |
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// TODO: segfaults if zero arguments given |
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// switch/case??? |
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if (argc == 1) { |
if (argc == 1) { |
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PRINTERROR("No arguments given, will segfault under cygwin. :-)"); |
PRINTERROR("No arguments given."); |
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exit(-1); |
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} |
} |
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// (3) range mode |
/* (3) range mode */ |
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if (argc > 2) { |
if (argc > 2) { |
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int i, j; |
long int i, j; |
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j = atoi(argv[2]); |
j = convert_number(argv[2]); |
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for (i = atoi(argv[1]); i< j; i++) { |
for (i = convert_number(argv[1]); i< j; i++) { |
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PRINTPRIME(i); |
PRINTPRIME(i); |
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} |
} |
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// other modes |
/* other modes */ |
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} else { |
} else { |
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// try to open file for reading |
/* try to open file for reading */ |
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FILE * fp = fopen(argv[1], "r"); |
FILE * fp = fopen(argv[1], "r"); |
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// (1) test-single-number mode: first argument is not a filename |
/* (1) test-single-number mode: first argument is not a filename */ |
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if (fp == NULL) { |
if (fp == NULL) { |
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PRINTPRIME(atoi(argv[1])); |
long int number = convert_number(argv[1]); |
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PRINTPRIME(number); |
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// (2) file mode: read numbers from file |
/* (2) file mode: read numbers from file */ |
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} else { |
} else { |
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char num[11]; |
char entry[11]; |
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while (fgets(num, 11, fp)) |
while (fgets(entry, 11, fp)) { |
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PRINTPRIME(atoi(num)); |
long int number = convert_number(entry); |
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PRINTPRIME(number); |
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} |
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fclose(fp); |
fclose(fp); |
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} |
} |
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} |
} |