Palindromic primes: Difference between revisions
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Catskill549 (talk | contribs) (added AWK) |
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=={{header|AWK}}== |
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<lang AWK> |
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# syntax: GAWK -f PALINDROMIC_PRIMES.AWK |
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BEGIN { |
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start = 1 |
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stop = 999 |
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for (i=start; i<=stop; i++) { |
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if (is_prime(i) && reverse(i) == i) { |
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printf("%d ",i) |
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count++ |
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} |
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} |
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printf("\nPalindromic primes %d-%d: %d\n",start,stop,count) |
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exit(0) |
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} |
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function is_prime(x, i) { |
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if (x <= 1) { |
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return(0) |
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} |
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for (i=2; i<=int(sqrt(x)); i++) { |
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if (x % i == 0) { |
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return(0) |
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} |
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} |
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return(1) |
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} |
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function reverse(str, i,rts) { |
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for (i=length(str); i>=1; i--) { |
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rts = rts substr(str,i,1) |
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} |
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return(rts) |
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} |
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</lang> |
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{{out}} |
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<pre> |
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2 3 5 7 11 101 131 151 181 191 313 353 373 383 727 757 787 797 919 929 |
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Palindromic primes 1-999: 20 |
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</pre> |
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=={{header|Factor}}== |
=={{header|Factor}}== |
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===Simple=== |
===Simple=== |