Anonymous user
Primality by trial division: Difference between revisions
m
→{{header|REXX}}: added checks for non-integers. -- ~~~~
m (→{{header|REXX}}: changed/added comments, add whitespace, simplified the checking for wee primes. -- ~~~~) |
m (→{{header|REXX}}: added checks for non-integers. -- ~~~~) |
||
Line 1,366:
/*──────────────────────────────────ISPRIME subroutine──────────────────*/
isprime: procedure; parse arg x /*get the number in question*/
if \datatype(x,'W') then return 0 /*X isn't an integer? Not prime.*/
if wordpos(x,'2 3 5 7')\==0 then return 1 /*is number a teacher's pet?*/
if x<2 | x//2==0 | x//3==0 then return 0 /*weed out the riff-raff. */
Line 1,423 ⟶ 1,424:
/*──────────────────────────────────ISPRIME subroutine──────────────────*/
isprime: procedure; parse arg x /*get integer to be investigated.*/
if \datatype(x,'W') then return 0 /*X isn't an integer? Not prime.*/
if x<11 then return wordpos(x,'2 3 5 7')\==0 /*is it a wee prime? */
if x//2==0 then return 0 /*eliminate the evens. */
|