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September 2017 Update

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Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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12
Task/Semiprime/REXX/semiprime-2.rexx
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@ -2,12 +2,16 @@
parse arg bot top . /*obtain optional arguments from the CL*/
if bot=='' | bot=="," then bot=random() /*None given? User wants us to guess.*/
if top=='' | top=="," then top=bot /*maybe define a range of numbers. */
w=max(length(bot), length(top)) /*obtain the maximum width of numbers. */
tell= top=>0 | top==bot /*should results be shown to the term? */
w=max(length(bot), length(top)) + 5 /*obtain the maximum width of numbers. */
numeric digits max(9, w) /*ensure there're enough decimal digits*/
do n=bot to top /*show results for a range of numbers. */
if isSemiPrime(n) then say right(n, w) " is semiprime."
else say right(n, w) " isn't semiprime."
#=0 /*initialize number of semiprimes found*/
do n=bot to abs(top) /*show results for a range of numbers. */
?=isSemiPrime(n); #=#+? /*Is N a semiprime?; Maybe bump counter*/
if tell then say right(n,w) right(word("isn't" 'is', ?+1), 6) 'semiprime.'
end /*n*/
say
if bot\==top then say 'found ' # " semiprimes."
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
isPrime: procedure; parse arg x; if x<2 then return 0 /*number too low?*/

41
Task/Semiprime/REXX/semiprime-3.rexx Normal file
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@ -0,0 +1,41 @@
/*REXX program determines if any integer (or a range of integers) is/are semiprime. */
parse arg bot top . /*obtain optional arguments from the CL*/
if bot=='' | bot=="," then bot=random() /*None given? User wants us to guess.*/
if top=='' | top=="," then top=bot /*maybe define a range of numbers. */
tell= bot=>0 & top=>0 /*should results be shown to the term? */
w=max(length(bot), length(top)) /*obtain the maximum width of numbers. */
!.=; !.2=1; !.3=1; !.5=1; !.7=1; !.11=1; !.13=1; !.17=1; !.19=1; !.23=1; !.29=1; !.31=1
numeric digits max(9, w) /*ensure there're enough decimal digits*/
#=0 /*initialize number of semiprimes found*/
do n=abs(bot) to abs(top) /*show results for a range of numbers. */
?=isSemiPrime(n); #=#+? /*Is N a semiprime?; Maybe bump counter*/
if tell then say right(n,w) right(word("isn't" 'is', ?+1), 6) 'semiprime.'
end /*n*/
say
if bot\==top then say 'found ' # " semiprimes."
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
isPrime: procedure expose !.; parse arg x; if x<2 then return 0 /*number too low?*/
if !.x==1 then return 1 /*a known prime. */
if x// 2==0 then return 0; if x//3==0 then return 0 /*÷ by 2;÷by 3?*/
parse var x '' -1 _; if _==5 then return 0 /*last digit a 5?*/
if x// 7==0 then return 0; if x//11==0 then return 0 /*÷ by 7;÷by 11?*/
if x//13==0 then return 0; if x//17==0 then return 0 /*÷ by 13;÷by 17?*/
if x//19==0 then return 0; if x//23==0 then return 0 /*÷ by 19;÷by 23?*/
do j=29 by 6 until j*j>x; if x//j==0 then return 0 /*not a prime. */
if x//(j+2)==0 then return 0 /* " " " */
end /*j*/
!.x=1; return 1 /*indicate that X is a prime number. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
isSemiPrime: procedure expose !.; parse arg x; if x<4 then return 0
do i=2 for 2; if x//i==0 then if isPrime(x%i) then return 1
else return 0
end /*i*/
/* ___ */
do j=5 by 6 until j*j>x /* > √ x ?*/
do k=j by 2 for 2; if x//k==0 then if isPrime(x%k) then return 1
else return 0
end /*k*/ /* [↑] see if 2nd factor is prime or ¬*/
end /*j*/ /* [↑] J is never a multiple of three.*/
return 0