50 lines
947 B
C
50 lines
947 B
C
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// C version of a Prime Number Finder
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// Alternate Algorithm: Instead of using sqrt function,
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// track it with two variables
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// haplo@mindstab.net
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#include <stdio.h>
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#include <stdlib.h>
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int check(int i, int cnt, int m)
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{
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if(i > m) return 1;
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else {
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if( (cnt%i)==0) return 0;
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return check(i+2,cnt, m);
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}
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}
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int primes(int c, int m, int sq, int sqm)
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{
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if(c > m) return 1; else
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{
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if(check(3,c,sq))
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printf("%d\n", c);
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if(c>=sqm) {
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sq++;
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sqm = sq*sq;
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}
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return primes(c+2, m, sq, sqm);
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}
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}
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int main(int argc, char **argv)
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{
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unsigned int i, x, max=2, isP, sqr=4;
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unsigned int MAX_NUM;
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if(argc < 2) {
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printf("primesaltc <MAX NUM>\n");
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return -1;
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} else {
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MAX_NUM = atoi(argv[1]);
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}
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if(MAX_NUM < 1)
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{
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printf("Invalid MAX_NUM specified\n");
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return -1;
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}
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primes(3, MAX_NUM, 2,4);
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}
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