Ascending primes: Difference between revisions
Added Algol W
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(Added Algol W) |
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34679 123457 123479 124567 124679 125789 134789 145679 234589 235679
235789 245789 345679 345689 1234789 1235789 1245689 1456789 12356789 23456789
</pre>
=={{header|ALGOL W}}==
{{Trans|Lua}}
...and only a few characters different from the Algol W [[Descending primes]] sample.
<syntaxhighlight lang="algolw">
begin % find all primes with strictly ascending digits - translation of Lua %
% quicksorts v, the bounds of v must be specified in lb and ub %
procedure quicksort ( integer array v( * )
; integer value lb, ub
) ;
if ub > lb then begin
% more than one element, so must sort %
integer left, right, pivot;
left := lb;
right := ub;
% choosing the middle element of the array as the pivot %
pivot := v( left + ( ( right + 1 ) - left ) div 2 );
while begin
while left <= ub and v( left ) < pivot do left := left + 1;
while right >= lb and v( right ) > pivot do right := right - 1;
left <= right
end do begin
integer swap;
swap := v( left );
v( left ) := v( right );
v( right ) := swap;
left := left + 1;
right := right - 1
end while_left_le_right ;
quicksort( v, lb, right );
quicksort( v, left, ub )
end quicksort ;
% returns true if n is prime, false otherwise %
logical procedure is_prime( integer value n ) ;
if n < 2 then false
else if n rem 2 = 0 then n = 2
else if n rem 3 = 0 then n = 3
else begin
logical prime; prime := true;
for f := 5 step 6 until entier( sqrt( n ) ) do begin
if n rem f = 0 or n rem ( f + 2 ) = 0 then begin
prime := false;
goto done
end if_n_rem_f_eq_0_or_n_rem_f_plus_2_eq_0
end for_f;
done: prime
end is_prime ;
% increments n and also returns its new value %
integer procedure inc ( integer value result n ) ; begin n := n + 1; n end;
% sets primes to the list of ascending primes and lenPrimes to the %
% number of ascending primes - primes must be big enough, e.g. have 511 %
% elements %
procedure ascending_primes ( integer array primes ( * )
; integer result lenPrimes
) ;
begin
integer array digits ( 1 :: 9 );
integer array candidates ( 1 :: 6000 );
integer lenCandidates;
candidates( 1 ) := 0;
lenCandidates := 1;
lenPrimes := 0;
for i := 1 until 9 do digits( i ) := i;
for i := 1 until 9 do begin
for j := 1 until lenCandidates do begin
integer cValue; cValue := candidates( j ) * 10 + digits( i );
if is_prime( cValue ) then primes( inc( lenPrimes ) ) := cValue;
candidates( inc( lenCandidates ) ) := cValue
end for_j
end for_i ;
quickSort( primes, 1, lenPrimes );
end ascending_primes ;
begin % find the ascending primes and print them %
integer array primes ( 1 :: 512 );
integer lenPrimes;
ascending_primes( primes, lenPrimes );
for i := 1 until lenPrimes do begin
writeon( i_w := 8, s_w := 0, " ", primes( i ) );
if i rem 10 = 0 then write()
end for_i
end
end.
</syntaxhighlight>
{{out}}
<pre>
2 3 5 7 13 17 19 23 29 37
47 59 67 79 89 127 137 139 149 157
167 179 239 257 269 347 349 359 367 379
389 457 467 479 569 1237 1249 1259 1279 1289
1367 1459 1489 1567 1579 1789 2347 2357 2389 2459
2467 2579 2689 2789 3457 3467 3469 4567 4679 4789
5689 12347 12379 12457 12479 12569 12589 12689 13457 13469
13567 13679 13789 15679 23459 23567 23689 23789 25679 34589
34679 123457 123479 124567 124679 125789 134789 145679 234589 235679
235789 245789 345679 345689 1234789 1235789 1245689 1456789 12356789 23456789
</pre>
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