Amicable pairs: Difference between revisions
Added Algol W
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(Added Algol W) |
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12285 and 14595 are an amicable pair
17296 and 18416 are an amicable pair
</pre>
=={{header|ALGOL W}}==
{{Trans|ALGOL 68}}
<syntaxhighlight lang="algolw">
begin % find amicable pairs p1, p2 where each is equal to the other's %
% proper divisor sum %
integer MAX_NUMBER;
MAX_NUMBER := 20000;
begin
integer array pdSum( 1 :: MAX_NUMBER ); % table of proper divisors %
for i := 1 until MAX_NUMBER do pdSum( i ) := 1;
for i := 2 until MAX_NUMBER do begin
for j := i + i step i until MAX_NUMBER do pdSum( j ) := pdSum( j ) + i
end for_i ;
% find the amicable pairs up to 20 000 %
for p1 := 1 until MAX_NUMBER - 1 do begin
integer pdSumP1;
pdSumP1 := pdSum( p1 );
if pdSumP1 > p1 and pdSumP1 <= MAX_NUMBER and pdSum( pdSumP1 ) = p1 then begin
write( i_w := 5, s_w := 0, p1, " and ", pdSumP1, " are an amicable pair" )
end if_pdSumP1_gt_p1_and_le_MAX_NUMBER
end for_p1
end
end.
</syntaxhighlight>
{{out}}
<pre>
220 and 284 are an amicable pair
1184 and 1210 are an amicable pair
2620 and 2924 are an amicable pair
5020 and 5564 are an amicable pair
6232 and 6368 are an amicable pair
10744 and 10856 are an amicable pair
12285 and 14595 are an amicable pair
17296 and 18416 are an amicable pair
</pre>
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