Largest difference between adjacent primes: Difference between revisions
Largest difference between adjacent primes (view source)
Revision as of 18:04, 19 November 2021
, 2 years agoAdded Algol 68
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Find and show on this page the largest difference between adjacent primes under 1,000,000.
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=={{header|ALGOL 68}}==
Note, to run this with Algol 68G, the command line option <code>--heap 256M</code> whould be specified on the command line to allow a larger heap size.<br>
As with the Wren, Phix, etc. samples, shows the gaps for at a few other places.
{{libheader|ALGOL 68-primes}}
<lang algol68>BEGIN # find the largest gap between adjacent primes up to 10 000 000 #
PR read "primes.incl.a68" PR
[]BOOL prime = PRIMESIEVE 10 000 000; # sieve the primes to 10 000 000 #
# find the largest gap between primes #
INT max gap := 0; # gap between 2 and 3 #
INT max prime := 0; # the prime with the maximum gap #
INT max prev := 0; # the prime before the maximum gap #
INT prev prime := 2; # the previous prime #
INT power of 10 := 10; # next number to print the gap for #
FOR i FROM 3 BY 2 TO UPB prime DO
IF prime[ i ] THEN
# have a prime #
INT gap = i - prev prime;
IF gap > max gap THEN
# have a bigger gap than before #
max prime := i;
max prev := prev prime;
max gap := gap
FI;
prev prime := i
FI;
IF i = power of 10 - 1 THEN
# have reached the next power of 10 - report the max gap so far #
print( ( "Largest gap between primes up to ", whole( power of 10, -9 )
, ": ", whole( max gap, -9 ), " between "
, whole( max prev, 0 ), " and ", whole( max prime, 0 )
, newline
)
);
power of 10 *:= 10
FI
OD
END</lang>
{{out}}
<pre>
Largest gap between primes up to 10: 2 between 3 and 5
Largest gap between primes up to 100: 8 between 89 and 97
Largest gap between primes up to 1000: 20 between 887 and 907
Largest gap between primes up to 10000: 36 between 9551 and 9587
Largest gap between primes up to 100000: 72 between 31397 and 31469
Largest gap between primes up to 1000000: 114 between 492113 and 492227
Largest gap between primes up to 10000000: 154 between 4652353 and 4652507
</pre>
=={{header|C}}==
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