Catalan numbers/Pascal's triangle: Difference between revisions

</pre>

=={{header|ALGOL W}}==

<lang algolw>begin

% print the first 15 Catalan numbers from Pascal's triangle %

integer n;

n := 15;

begin

integer array pascalLine ( 1 :: n + 1 );

% the Catalan numbers are the differences between the middle and middle - 1 numbers of the odd %

% lines of Pascal's triangle (lines with 3 or more numbers) %

% note - we only need to calculate the left side of the triangle %

pascalLine( 1 ) := 1;

for c := 2 until n + 1 do begin

% even line %

for i := c - 1 step -1 until 2 do pascalLine( i ) := pascalLine( i - 1 ) + pascalLine( i );

pascalLine( c ) := pascalLine( c - 1 );

% odd line %

for i := c step -1 until 2 do pascalLine( i ) := pascalLine( i - 1 ) + pascalLine( i );

writeon( i_w := 1, s_w := 0, " ", pascalLine( c ) - pascalLine( c - 1 ) )

end for_c

end

end.</lang>

{{out}}

<pre>

1 2 5 14 42 132 429 1430 4862 16796 58786 208012 742900 2674440 9694845