Palindromic primes in base 16: Difference between revisions

=={{header|Action!}}==

{{libheader|Action! Sieve of Eratosthenes}}

<lang Action!>INCLUDE "H6:SIEVE.ACT"

BYTE FUNC Palindrome(CHAR ARRAY s)

BYTE l,r

l=1 r=s(0)

WHILE l<r

DO

IF s(l)#s(r) THEN RETURN (0) FI

l==+1 r==-1

OD

RETURN (1)

PROC IntToHex(INT i CHAR ARRAY hex)

CHAR ARRAY digits="0123456789ABCDEF"

BYTE d

hex(0)=0

WHILE i#0

DO

d=i MOD 16

hex(0)==+1

hex(hex(0))=digits(d+1)

i==/16

OD

RETURN

BYTE Func IsPalindromicPrime(INT i CHAR ARRAY hex

BYTE ARRAY primes)

BYTE d

INT rev,tmp

IF primes(i)=0 THEN

RETURN (0)

FI

IntToHex(i,hex)

IF Palindrome(hex) THEN

RETURN (1)

FI

RETURN (0)

PROC Main()

DEFINE MAX="499"

BYTE ARRAY primes(MAX+1)

INT i,count=[0]

CHAR ARRAY hex(5)

Put(125) PutE() ;clear the screen

Sieve(primes,MAX+1)

FOR i=2 TO MAX

DO

IF IsPalindromicPrime(i,hex,primes) THEN

Print(hex) Put(32)

count==+1

FI

OD

PrintF("%EThere are %I palindromic primes",count)

RETURN</lang>

{{out}}

[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Palindromic_primes_in_base_16.png Screenshot from Atari 8-bit computer]

<pre>

2 3 5 7 B D 11 101 151 161 191 1B1 1C1

There are 13 palindromic primes

</pre>