59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
/*
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* Copyright (C) 2020 Ortega Froysa, Nicolás <nicolas@ortegas.org>
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* Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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int main(int argc, char *argv[]) {
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if(argc < 2)
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{
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fprintf(stderr, "Insufficient number of arguments. Use '-h' for more options.\n");
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return 2;
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}
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else if(argc > 2)
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{
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fprintf(stderr, "Too many arguments. Use '-h' for more options.\n");
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return 2;
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}
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if(strcmp(argv[1], "-h") == 0)
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{
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printf("USAGE: %s <number> | -h\n\n", argv[0]);
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puts("Calculates to see if a given number is prime, and returns success or\nfailure return code.\n");
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puts("OPTIONS:");
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puts(" <number> number to test");
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puts(" -h show this help information");
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return 0;
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}
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char *end;
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unsigned long long int test_num =
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strtoll(argv[1], &end, 10);
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if(test_num % 2 == 0)
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return 1;
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unsigned long long int test_root = sqrt(test_num);
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for(unsigned long long int i = 3; i < test_root; i += 2)
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{
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if(test_num % i == 0)
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return 1;
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}
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return 0;
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}
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