Strong and weak primes: Difference between revisions
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→{{header|EasyLang}}
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=={{header|11l}}==
<
V is_prime = [0B] * 2 [+] [1B] * (limit - 1)
L(n) 0 .< Int(limit ^ 0.5 + 1.5)
Line 64:
print(‘The count of balanced primes below 10,000,000: ’b.len)
print("\nTOTAL primes below 1,000,000: "sum(p.filter(pr -> pr < 1'000'000).map(pr -> 1)))
print(‘TOTAL primes below 10,000,000: ’p.len)</
{{out}}
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=={{header|ALGOL 68}}==
{{works with|ALGOL 68G|Any - tested with release 2.8.3.win32}}
<
PR heap=128M PR # set heap memory size for Algol 68G #
# returns a string representation of n with commas #
Line 178:
print( ( newline ) );
print( ( " weak primes below 1,000,000: ", commatise( weak1 ), newline ) );
print( ( " weak primes below 10,000,000: ", commatise( weak10 ), newline ) )</
{{out}}
<pre>
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</pre>
=={{header|AWK}}==
<syntaxhighlight lang="awk">
# syntax: GAWK -f STRONG_AND_WEAK_PRIMES.AWK
BEGIN {
Line 256:
return(1)
}
</syntaxhighlight>
{{out}}
<pre>
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=={{header|C}}==
{{trans|D}}
<
#include <stdint.h>
#include <stdio.h>
Line 390:
free(primePtr);
return EXIT_SUCCESS;
}</
{{out}}
<pre>First 36 strong primes: 11 17 29 37 41 59 67 71 79 97 101 107 127 137 149 163 179 191 197 223 227 239 251 269 277 281 307 311 331 347 367 379 397 419 431 439
Line 402:
=={{header|C sharp}}==
{{works with|C sharp|7}}
<
using static System.Linq.Enumerable;
using System;
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}
}</
{{out}}
<pre>
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=={{header|C++}}==
<
#include <iostream>
#include <iterator>
Line 493:
weak_primes.print(std::cout, "weak");
return 0;
}</
Contents of prime_sieve.hpp:
<
#define PRIME_SIEVE_HPP
Line 547:
}
#endif</
{{out}}
Line 560:
=={{header|D}}==
<
import std.array;
import std.range;
Line 653:
writefln("There are %d weak primes below 1,000,000", weakPrimes.filter!"a<1_000_000".count);
writefln("There are %d weak primes below 10,000,000", weakPrimes.filter!"a<10_000_000".count);
}</
{{out}}
<pre>First 36 strong primes: [11, 17, 29, 37, 41, 59, 67, 71, 79, 97, 101, 107, 127, 137, 149, 163, 179, 191, 197, 223, 227, 239, 251, 269, 277, 281, 307, 311, 331, 347, 367, 379, 397, 419, 431, 439]
Line 661:
There are 37780 weak primes below 1,000,000
There are 321750 weak primes below 10,000,000</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
procedure StrongWeakPrimes(Memo: TMemo);
{Display Strong/Weak prime information}
var I,P: integer;
var Sieve: TPrimeSieve;
var S: string;
var Cnt,Cnt1,Cnt2: integer;
type TPrimeTypes = (ptStrong,ptWeak,ptBalanced);
function GetTypeStr(PrimeType: TPrimeTypes): string;
{Get string describing PrimeType}
begin
case PrimeType of
ptStrong: Result:='Strong';
ptWeak: Result:='Weak';
ptBalanced: Result:='Balanced';
end;
end;
function GetPrimeType(N: integer): TPrimeTypes;
{Return flag indicating type of prime Primes[N] is}
{Strong = Primes(N) > [Primes(N-1) + Primes(N+1)] / 2}
{Weak = Primes(N) < [Primes(N-1) + Primes(N+1)] / 2}
{Balanced = Primes(N) = [Primes(N-1) + Primes(N+1)] / 2}
var P,P1: double;
begin
P:=Sieve.Primes[N];
P1:=(Sieve.Primes[N-1] + Sieve.Primes[N+1]) / 2;
if P>P1 then Result:=ptStrong
else if P<P1 then Result:=ptWeak
else Result:=ptBalanced;
end;
procedure GetPrimeCounts(PT: TPrimeTypes; var Cnt1,Cnt2: integer);
{Get number of primes of type "PT" below 1 million and 10 million}
var I: integer;
begin
Cnt1:=0; Cnt2:=0;
for I:=1 to 1000000-1 do
begin
if GetPrimeType(I)=PT then
begin
if Sieve.Primes[I]>10000000 then break;
Inc(Cnt2);
if Sieve.Primes[I]<1000000 then Inc(Cnt1);
end;
end;
end;
function GetPrimeList(PT: TPrimeTypes; Limit: integer): string;
{Get a list of primes of type PT up to Limit}
var I,Cnt: integer;
begin
Result:='';
Cnt:=0;
for I:=1 to Sieve.PrimeCount-1 do
if GetPrimeType(I)=PT then
begin
Inc(Cnt);
P:=Sieve.Primes[I];
Result:=Result+Format('%5d',[P]);
if Cnt>=Limit then break;
if (Cnt mod 10)=0 then Result:=Result+CRLF;
end;
end;
procedure ShowPrimeTypeData(PT: TPrimeTypes; Limit: Integer);
{Display information about specified PrimeType, listing items up to Limit}
var S,TS: string;
begin
S:=GetPrimeList(PT,Limit);
TS:=GetTypeStr(PT);
Memo.Lines.Add(Format('First %d %s primes are:',[Limit,TS]));
Memo.Lines.Add(S);
GetPrimeCounts(PT,Cnt1,Cnt2);
Memo.Lines.Add(Format('Number %s primes <1,000,000: %8.0n', [TS,Cnt1+0.0]));
Memo.Lines.Add(Format('Number %s primes <10,000,000: %8.0n', [TS,Cnt2+0.0]));
Memo.Lines.Add('');
end;
begin
Sieve:=TPrimeSieve.Create;
try
Sieve.Intialize(200000000);
Memo.Lines.Add('Primes in Sieve : '+IntToStr(Sieve.PrimeCount));
ShowPrimeTypeData(ptStrong,36);
ShowPrimeTypeData(ptWeak,37);
ShowPrimeTypeData(ptBalanced,28);
finally Sieve.Free; end;
end;
</syntaxhighlight>
{{out}}
<pre>
Primes in Sieve : 11078937
First 36 Strong primes are:
11 17 29 37 41 59 67 71 79 97
101 107 127 137 149 163 179 191 197 223
227 239 251 269 277 281 307 311 331 347
367 379 397 419 431 439
Number Strong primes <1,000,000: 37,723
Number Strong primes <10,000,000: 320,991
First 37 Weak primes are:
3 7 13 19 23 31 43 47 61 73
83 89 103 109 113 131 139 151 167 181
193 199 229 233 241 271 283 293 313 317
337 349 353 359 383 389 401
Number Weak primes <1,000,000: 37,780
Number Weak primes <10,000,000: 321,750
First 28 Balanced primes are:
5 53 157 173 211 257 263 373 563 593
607 653 733 947 977 1103 1123 1187 1223 1367
1511 1747 1753 1907 2287 2417 2677 2903
Number Balanced primes <1,000,000: 2,994
Number Balanced primes <10,000,000: 21,837
Elapsed Time: 2.947 Sec.
</pre>
=={{header|EasyLang}}==
<syntaxhighlight>
fastfunc isprim num .
i = 3
while i <= sqrt num
if num mod i = 0
return 0
.
i += 2
.
return 1
.
func nextprim n .
repeat
n += 2
until isprim n = 1
.
return n
.
proc strwkprimes ncnt sgn . .
write "First " & ncnt & ": "
pr2 = 2
pr3 = 3
repeat
pr1 = pr2
pr2 = pr3
until pr2 >= 10000000
pr3 = nextprim pr3
if pr1 < 1000000 and pr2 > 1000000
print ""
print "Count lower 10e6: " & cnt
.
if sgn * pr2 > sgn * (pr1 + pr3) / 2
cnt += 1
if cnt <= ncnt
write pr2 & " "
.
.
.
print "Count lower 10e7: " & cnt
print ""
.
print "Strong primes:"
strwkprimes 36 1
print "Weak primes:"
strwkprimes 37 -1
</syntaxhighlight>
{{out}}
<pre>
Strong primes:
First 36: 11 17 29 37 41 59 67 71 79 97 101 107 127 137 149 163 179 191 197 223 227 239 251 269 277 281 307 311 331 347 367 379 397 419 431 439
Count lower 10e6: 37723
Count lower 10e7: 320991
Weak primes:
First 37: 3 7 13 19 23 31 43 47 61 73 83 89 103 109 113 131 139 151 167 181 193 199 229 233 241 271 283 293 313 317 337 349 353 359 383 389 401
Count lower 10e6: 37780
Count lower 10e7: 321750
</pre>
=={{header|Factor}}==
<
tools.memory.private ;
IN: rosetta-code.strong-primes
Line 687 ⟶ 883:
First 37 weak primes:\n%[%d, %]
%s weak primes below 1,000,000
%s weak primes below 10,000,000\n" printf</
{{out}}
<pre>
Line 702 ⟶ 898:
=={{header|FreeBASIC}}==
<
#include "isprime.bas"
Line 762 ⟶ 958:
wend
print "There are ";c;" weak primes below ten million"
print</
{{out}}<pre>
The first 36 strong primes are:
Line 776 ⟶ 972:
=={{header|Frink}}==
<
strongPrimes[end=undef] := select[primes[3,end], {|p| p > (previousPrime[p] + nextPrime[p])/2 }]
weakPrimes[end=undef] := select[primes[3,end], {|p| p < (previousPrime[p] + nextPrime[p])/2 }]
Line 787 ⟶ 983:
println["Weak primes below 1,000,000: " + length[weakPrimes[1_000_000]]]
println["Weak primes below 10,000,000: " + length[weakPrimes[10_000_000]]]
</syntaxhighlight>
{{out}}
Line 800 ⟶ 996:
=={{header|Go}}==
<
import "fmt"
Line 885 ⟶ 1,081:
fmt.Println("\nThe number of weak primes below 1,000,000 is", commatize(count))
fmt.Println("\nThe number of weak primes below 10,000,000 is", commatize(len(weak)))
}</
{{out}}
Line 905 ⟶ 1,101:
=={{header|Haskell}}==
Uses primes library: http://hackage.haskell.org/package/primes-0.2.1.0/docs/Data-Numbers-Primes.html
<
import Data.Numbers.Primes (primes)
Line 923 ⟶ 1,119:
printf "Weak primes below 10,000,000: %d\n\n" . length . takeWhile (<10000000) $ weakPrimes
where strongPrimes = xPrimes (>) primes
weakPrimes = xPrimes (<) primes</
{{out}}
<pre>
Line 966 ⟶ 1,162:
=={{header|Java}}==
<
public class StrongAndWeakPrimes {
Line 1,071 ⟶ 1,267:
}
</syntaxhighlight>
{{out}}
<pre>
Line 1,082 ⟶ 1,278:
Number of weak primes below 1,000,000 = 37,780
Number of weak primes below 10,000,000 = 321,750
</pre>
=={{header|jq}}==
{{Works with|jq}}
'''Also works with gojq, the Go implementation of jq'''
The following assumes that `primes` generates a stream of primes less
than or equal to `.`
as defined, for example, at [[Sieve_of_Eratosthenes#jq|Sieve of Eratosthenes]]]].
<syntaxhighlight lang=jq>
def count(s): reduce s as $_ (0; .+1);
# Emit {strong, weak} primes up to and including $n
def strong_weak_primes:
. as $n
| primes as $primes
| ("\nCheck: last prime generated: \($primes[-1])" | debug) as $debug
| reduce range(1; $primes|length-1) as $p ({};
(($primes[$p-1] + $primes[$p+1]) / 2) as $x
| if $primes[$p] > $x
then .strong += [$primes[$p]]
elif $primes[$p] < $x
then .weak += [$primes[$p]]
else .
end );
(1e7 + 19)
| strong_weak_primes as {$strong, $weak}
| "The first 36 strong primes are:",
$strong[:36],
"\nThe count of the strong primes below 1e6: \(count($strong[]|select(. < 1e6 )))",
"\nThe count of the strong primes below 1e7: \(count($strong[]|select(. < 1e7 )))",
"\nThe first 37 weak primes are:",
$weak[:37],
"\nThe count of the weak primes below 1e6: \(count($weak[]|select(. < 1e6 )))",
"\nThe count of the weak primes below 1e7: \(count($weak[]|select(. < 1e7 )))"
</syntaxhighlight>
{{output}}
<pre>
The first 36 strong primes are:
[11,17,29,37,41,59,67,71,79,97,101,107,127,137,149,163,179,191,197,223,227,239,251,269,277,281,307,311,331,347,367,379,397,419,431,439]
The count of the strong primes below 1e6: 37723
The count of the strong primes below 1e7: 320991
The first 37 weak primes are:
[3,7,13,19,23,31,43,47,61,73,83,89,103,109,113,131,139,151,167,181,193,199,229,233,241,271,283,293,313,317,337,349,353,359,383,389,401]
The count of the weak primes below 1e6: 37780
The count of the weak primes below 1e7: 321750
</pre>
=={{header|Julia}}==
<
function parseprimelist()
Line 1,117 ⟶ 1,367:
parseprimelist()
</
The first 36 strong primes are: [11, 17, 29, 37, 41, 59, 67, 71, 79, 97, 101, 107, 127, 137, 149, 163, 179, 191, 197, 223, 227, 239, 251, 269, 277, 281, 307, 311, 331, 347, 367, 379, 397, 419, 431, 439]
There are 37,723 stromg primes less than 1 million.
Line 1,131 ⟶ 1,381:
=={{header|Kotlin}}==
{{trans|Java}}
<
private val primes = BooleanArray(MAX)
Line 1,233 ⟶ 1,483:
}
}
}</
{{out}}
<pre>First 36 strong primes:
Line 1,245 ⟶ 1,495:
=={{header|Ksh}}==
<
#!/bin/ksh
Line 1,334 ⟶ 1,584:
printf "Number of Weak Primes under %d is: %d\n" $GOAL1 ${goal1_weak}
printf "Number of Weak Primes under %d is: %d\n\n\n" $MAX_INT ${wpcnt}
printf "Number of Balanced Primes under %d is: %d\n\n\n" $MAX_INT ${bpcnt}</
{{out}}<pre>
Total primes under 10000000 = 664579
Line 1,353 ⟶ 1,603:
=={{header|Lua}}==
This could be made faster but favours readability. It runs in about 3.3 seconds in LuaJIT on a 2.8 GHz core.
<
function primeList (n)
local function isPrime (x)
Line 1,405 ⟶ 1,655:
for i = 1, 37 do io.write(weak[i] .. " ") end
print("\n\nThere are " .. wCount .. " weak primes below one million.")
print("\nThere are " .. #weak .. " weak primes below ten million.")</
{{out}}
<pre>The first 36 strong primes are:
Line 1,423 ⟶ 1,673:
=={{header|Maple}}==
<
holder := false;
if isprime(n) and 1/2*prevprime(n) + 1/2*nextprime(n) < n then
Line 1,466 ⟶ 1,716:
countStrong(10000000)
countWeak(1000000)
countWeak(10000000)</
{{Out}}
<pre>[11, 17, 29, 37, 41, 59, 67, 71, 79, 97, 101, 107, 127, 137, 149, 163, 179, 191, 197, 223, 227, 239, 251, 269, 277, 281, 307, 311, 331, 347, 367, 379, 397, 419, 431, 439]
Line 1,476 ⟶ 1,726:
=={{header|Mathematica}}/{{header|Wolfram Language}}==
<
SequenceCases[p, ({a_, b_, c_}) /; (a + c < 2 b) :> b, 36, Overlaps -> True]
SequenceCases[p, ({a_, b_, c_}) /; (a + c > 2 b) :> b, 37, Overlaps -> True]
Line 1,484 ⟶ 1,734:
p = Prime[Range[PrimePi[10^7] + 1]];
Length[Select[Partition[p, 3, 1], #[[3]] + #[[1]] < 2 #[[2]] &]]
Length[Select[Partition[p, 3, 1], #[[3]] + #[[1]] > 2 #[[2]] &]]</
{{out}}
<pre>{11,17,29,37,41,59,67,71,79,97,101,107,127,137,149,163,179,191,197,223,227,239,251,269,277,281,307,311,331,347,367,379,397,419,431,439}
Line 1,495 ⟶ 1,745:
=={{header|Nim}}==
<
const
Line 1,542 ⟶ 1,792:
echo " ", weakPrimes[0..36].join(" ")
echo "Count of weak primes below 1_000_000: ", weakPrimes.count(1_000_000)
echo "Count of weak primes below 10_000_000: ", weakPrimes.count(10_000_000)</
{{out}}
Line 1,561 ⟶ 1,811:
If deltaAfter < deltaBefore than a strong prime is found.
<
{$IFNDEF FPC}
{$AppType CONSOLE}
Line 1,729 ⟶ 1,979:
WeakOut(37);
CntWeakStrong10(CntWs);
end.</
{{Out}}
<pre>
Line 1,752 ⟶ 2,002:
{{trans|Raku}}
{{libheader|ntheory}}
<
sub comma {
Line 1,779 ⟶ 2,029:
print "Count of $type primes <= @{[comma $c1]}: " . comma below($c1,@$pr) . "\n";
print "Count of $type primes <= @{[comma $c2]}: " . comma scalar @$pr . "\n";
}</
{{out}}
<pre>
Line 1,799 ⟶ 2,049:
=={{header|Phix}}==
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">strong</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span> <span style="color: #000000;">weak</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">2</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">get_maxprime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e14</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #000080;font-style:italic;">-- (ie idx of primes < (sqrt(1e14)==1e7), bar 1st)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">c</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">compare</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">,(</span><span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)+</span><span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">))/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=+</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">strong</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">p</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=-</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">weak</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">p</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first thirty six strong primes: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">shorten</span><span style="color: #0000FF;">(</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">36</span><span style="color: #0000FF;">],</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%2d"</span><span style="color: #0000FF;">),</span><span style="color: #008000;">", "</span><span style="color: #0000FF;">)})</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first thirty seven weak primes: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">shorten</span><span style="color: #0000FF;">(</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">37</span><span style="color: #0000FF;">],</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%2d"</span><span style="color: #0000FF;">),</span><span style="color: #008000;">", "</span><span style="color: #0000FF;">)})</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %,d strong primes below %,d and %,d below %,d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">))-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">),</span><span style="color: #000000;">1e7</span><span style="color: #0000FF;">})</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %,d weak primes below %,d and %,d below %,d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">))-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">),</span><span style="color: #000000;">1e7</span><span style="color: #0000FF;">})</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
The first
The first
</pre>
=={{header|PureBasic}}==
<
Global Dim P.b(#MAX) : FillMemory(@P(),#MAX,1,#PB_Byte)
Global NewList Primes.i()
Line 1,863 ⟶ 2,109:
PrintN("Number of weak primes below 1'000'000 = "+FormatNumber(c2,0,".","'"))
PrintN("Number of weak primes below 10'000'000 = "+FormatNumber(ListSize(Weak()),0,".","'"))
Input()</
{{out}}
<pre>First 36 strong primes:
Line 1,879 ⟶ 2,125:
COmputes and shows the requested output then adds similar output for the "balanced" case where <code>prime(p) == [prime(p-1) + prime(p+1)] ÷ 2</code>.
<
def primesfrom2to(n):
Line 1,915 ⟶ 2,161:
print('\nTOTAL primes below 1,000,000:',
sum(1 for pr in p if pr < 1_000_000))
print('TOTAL primes below 10,000,000:', len(p))</
{{out}}
Line 1,938 ⟶ 2,184:
{{works with|Rakudo|2018.11}}
<syntaxhighlight lang="raku"
use Math::Primesieve;
Line 1,963 ⟶ 2,209:
say "Count of $type primes <= {comma 1e6}: ", comma +@pr[^(@pr.first: * > 1e6,:k)];
say "Count of $type primes <= {comma 1e7}: ", comma +@pr;
}</
{{out}}
<pre>First 36 strong primes:
Line 1,981 ⟶ 2,227:
=={{header|REXX}}==
<
parse arg N kind _ . 1 . okind; upper kind /*obtain optional arguments from the CL*/
if N=='' | N=="," then N= 36 /*Not specified? Then assume default.*/
Line 2,030 ⟶ 2,276:
else return 0 /*not " " " */
else if y>s then return add() /*is an strong prime.*/
return 0 /*not " " " */</
This REXX program makes use of '''LINESIZE''' REXX program (or
BIF) which is used to determine the screen width (or linesize) of the
Line 2,069 ⟶ 2,315:
=={{header|Ring}}==
<
load "stdlib.ring"
Line 2,174 ⟶ 2,420:
see "weak primes below 1,000,000: " + primes2 + nl
see "weak primes below 10,000,000: " + primes3 + nl
</syntaxhighlight>
Output:
<pre>
Line 2,188 ⟶ 2,434:
=={{header|Ruby}}==
<
strong_gen = Enumerator.new{|y| Prime.each_cons(3){|a,b,c|y << b if a+c-b<b} }
Line 2,207 ⟶ 2,453:
puts "#{strongs} strong primes and #{weaks} weak primes below #{limit}."
end
</syntaxhighlight>
{{out}}
<pre>First 36 strong primes:
Line 2,220 ⟶ 2,466:
=={{header|Rust}}==
<
for i in 2..n {
if i * i > n {
Line 2,315 ⟶ 2,561:
}
println!("weak primes below 10,000,000: {}", n);
}</
<pre>
First 36 strong primes: 11 17 29 37 41 59 67 71 79 97 101 107 127 137 149 163 179 191 197 223 227 239 251 269 277 281 307 311 331 347 367 379 397 419 431 439
Line 2,327 ⟶ 2,573:
=={{header|Scala}}==
This example works entirely with lazily evaluated lists. It starts with a list of primes, and generates a sliding iterator that looks at each triplet of primes. Lists of strong and weak primes are built by applying the given filters then selecting the middle term from each triplet.
<
def main(args: Array[String]): Unit = {
val bnd = 1000000
Line 2,344 ⟶ 2,590:
def primeTrips: Iterator[LazyList[Int]] = primes.sliding(3)
def primes: LazyList[Int] = 2 #:: LazyList.from(3, 2).filter(n => !Iterator.range(3, math.sqrt(n).toInt + 1, 2).exists(n%_ == 0))
}</
{{out}}
Line 2,357 ⟶ 2,603:
=={{header|Sidef}}==
{{trans|Raku}}
<
var (*strong, *weak, *balanced)
Line 2,379 ⟶ 2,625:
say ("Count of #{type} primes <= #{c1.commify}: ", pr.first_index { _ > 1e6 }.commify)
say ("Count of #{type} primes <= #{c2.commify}: " , pr.len.commify)
}</
{{out}}
<pre>
Line 2,399 ⟶ 2,645:
=={{header|Swift}}==
<
class PrimeSieve {
Line 2,490 ⟶ 2,736:
strongPrimes.printInfo(name: "strong")
weakPrimes.printInfo(name: "weak")</
{{out}}
Line 2,505 ⟶ 2,751:
{{libheader|Wren-math}}
{{libheader|Wren-fmt}}
<
import "./fmt" for Fmt
var primes = Int.primeSieve(1e7 + 19) // next prime above 10 million
Line 2,527 ⟶ 2,773:
Fmt.print("$d", weak.take(37))
Fmt.print("\nThe count of the weak primes below $,d is $,d.", 1e6, weak.count{ |n| n < 1e6 })
Fmt.print("\nThe count of the weak primes below $,d is $,d.", 1e7, weak.count{ |n| n < 1e7 })</
{{out}}
Line 2,547 ⟶ 2,793:
=={{header|XPL0}}==
<
int Num, Dig, Cnt;
[Cnt:= [0];
Line 2,605 ⟶ 2,851:
NumOut(WeakCnt);
CrLf(0);
]</
{{out}}
Line 2,624 ⟶ 2,870:
[[Extensible prime generator#zkl]] could be used instead.
<
const N=1e7;
Line 2,636 ⟶ 2,882:
}
ps.pop(0); ps.append(pw.nextPrime().toInt());
}while(pn<=N);</
<
println("First %d %s primes:\n%s".fmt(psz,nm,list[0,psz].concat(" ")));
println("Count of %s primes <= %,10d: %,8d"
.fmt(nm,1e6,list.reduce('wrap(s,p){ s + (p<=1e6) },0)));
println("Count of %s primes <= %,10d: %,8d\n".fmt(nm,1e7,list.len()));
}</
{{out}}
<pre>
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