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#include <stdio.h> |
#include <stdio.h> |
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#define PRINTPRIME(x) if(prime(x)) printf("%i\n", x) |
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int prime(int number) |
#define PRINTPRIME(x) if(is_prime(x)) printf("%i\n", x) |
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#define PRINTERROR(message) printf("ERROR: %s\n", message) |
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// check for prime number |
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int is_prime(int number) |
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{ |
{ |
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int i; |
int i; |
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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 0; |
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} |
} |
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return 1; |
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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int i, j; |
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FILE * fp; |
// TODO: segfaults if zero arguments given |
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char num[11]; |
// switch/case??? |
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if(argc > 2 ){ |
if (argc == 1) { |
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j=atoi(argv[2]); |
PRINTERROR("No arguments given, will segfault under cygwin. :-)"); |
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for(i=atoi(argv[1]) ; i< j; i++){ |
} |
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// (3) range mode |
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if (argc > 2) { |
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int i, j; |
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j = atoi(argv[2]); |
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for (i = atoi(argv[1]); i< j; i++) { |
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PRINTPRIME(i); |
PRINTPRIME(i); |
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} |
} |
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}else { |
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fp=fopen(argv[1], "r"); |
// other modes |
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if(fp==NULL){ |
} else { |
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// try to open file for reading |
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FILE * fp = fopen(argv[1], "r"); |
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// (1) test-single-number mode: first argument is not a filename |
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if (fp == NULL) { |
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PRINTPRIME(atoi(argv[1])); |
PRINTPRIME(atoi(argv[1])); |
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}else{ |
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while(fgets(num, 11, fp)) |
// (2) file mode: read numbers from file |
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} else { |
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char num[11]; |
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while (fgets(num, 11, fp)) |
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PRINTPRIME(atoi(num)); |
PRINTPRIME(atoi(num)); |
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fclose(fp); |
fclose(fp); |
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} |
} |