Substring primes: Difference between revisions
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</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
function IsSubstringPrime(N: integer): boolean;
begin
if not IsPrime(N) then Result:=False
else if n < 10 then Result:=True
else if not IsPrime(N mod 100) then Result:=False
else if not IsPrime(N mod 10) then Result:=False
else if not IsPrime(N div 10) then Result:=False
else if n < 100 then Result:=True
else if not IsPrime(N div 100) then Result:=False
else if not IsPrime((N mod 100) div 10) then Result:=False
else Result:=True;
end;
procedure ShowSubtringPrimes(Memo: TMemo);
var N: integer;
begin
for N:=2 to 500-1 do
if IsSubstringPrime(N) then Memo.Lines.Add(IntToStr(N));
end;
</syntaxhighlight>
{{out}}
<pre>
2
3
5
7
23
37
53
73
373
Elapsed Time: 8.708 ms.
</pre>
=={{header|Factor}}==
Line 971 ⟶ 1,016:
Found 9 numbers in which all substrings are primes
done...
</pre>
=={{header|Rust}}==
<syntaxhighlight lang="rust">use primes::is_prime;
fn counted_prime_test() {
let mut number_of_prime_tests = 0;
let mut non_primes = vec![0; 0];
// start with 1 digit primes
let mut results: Vec<i32> = [2, 3, 5, 7].to_vec();
// check 2 digit candidates
for n in results.clone() {
for i in [3, 7].to_vec() {
if n != i {
let candidate = n * 10 + i;
if candidate < 100 {
number_of_prime_tests += 1;
if is_prime(candidate as u64) {
results.push(candidate);
} else {
non_primes.push(candidate);
}
}
}
}
}
// check 3 digit candidates
for n in results.clone() {
for i in [3, 7].to_vec() {
if 10 < n && n < 100 && n % 10 != i {
let candidate = n * 10 + i;
number_of_prime_tests += 1;
if is_prime(candidate as u64) {
results.push(candidate);
} else {
non_primes.push(candidate);
}
}
}
}
println!("Results: {results:?}.\nThe function isprime() was called {number_of_prime_tests} times.");
println!("Discarded nonprime candidates: {non_primes:?}");
println!("Because 237, 537, and 737 are excluded, we cannot generate any larger candidates from 373.");
}
fn main() {
counted_prime_test();
}
</syntaxhighlight>{{out}}
<pre>
Results: [2, 3, 5, 7, 23, 37, 53, 73, 373].
The function isprime() was called 10 times.
Discarded nonprime candidates: [27, 57, 237, 537, 737]
Because 237, 537, and 737 are already excluded, we cannot generate any larger candidates from 373.
</pre>
=={{header|RPL}}==
≪ { 2 3 5 7 } { } 0 1 → winners losers tests index
≪ 3
'''DO'''
winners index GET 10 * OVER + SWAP
'''IF''' 7 == '''THEN''' 3 'index' 1 STO+ '''ELSE''' 7 '''END'''
SWAP 1 CF
'''IF''' DUP 3 MOD OVER 100 MOD 11 MOD AND '''THEN'''
'''IF''' DUP ISPRIME? 'tests' 1 STO+ 1 FS '''THEN'''
'''IF''' DUP 100 MOD ISPRIME? 'tests' 1 STO+ 1 FS '''THEN''' 'winners' OVER STO+ 1 CF
'''END END END'''
'''IF''' 1 FS? '''THEN''' 'losers' OVER STO+ '''END'''
'''UNTIL''' 500 > '''END'''
DROP winners losers tests
≫ ≫ '<span style="color:blue">A085823</span>' STO
{{out}}
<pre>
3: { 2 3 5 7 23 37 53 73 373 }
2: { }
1: 10
</pre>
Line 981 ⟶ 1,103:
for j in (indices) {
parts << [array
i = j+1
}
Line 1,065 ⟶ 1,187:
===Using a limit===
<syntaxhighlight lang="
var primes = Int.primeSieve(499)
var sprimes = []
Line 1,092 ⟶ 1,214:
===Advanced===
This follows the logic in the OEIS A085823 comments.
<syntaxhighlight lang="
var results = [2, 3, 5, 7] // number must begin with a prime digit
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