Truncatable primes: Difference between revisions

=={{header|Pike}}==

<lang Pike>

array get_primes(int roof)

{

int p = 2;

array primes = ({});

do {

primes += ({ p });

p = p->next_prime();

} while (p < roof);

return primes;

}

bool is_prime(int candidate)

{

if( (candidate-1)->next_prime() == candidate )

return true;

return false;

}

bool is_lt_prime(int p)

{

while(p) {

if( !is_prime(p) )

return false;

p = (int)p->digits()[1..];

}

return true;

}

bool is_rt_prime(int p)

{

while(p) {

if( !is_prime(p) )

return false;

p = (int)p->digits()[..<1];

}

return true;

}

void main()

{

array primes = get_primes( 10->pow(6) );

bool ltp_found, rtp_found;

foreach( reverse(primes), int prime ) {

if( !ltp_found && is_lt_prime(prime) ) {

ltp_found = true;

write("Largest LTP: %d\n", prime);

}

if( !rtp_found && is_rt_prime(prime) ) {

rtp_found = true;

write("Largest RTP: %d\n", prime);

}

if(ltp_found && rtp_found)

break;

}

}

</lang>