Pascal's triangle: Difference between revisions

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m (added whitespace before the TOC (Table Of Contents), added a Task (bold) header. split the task's requirement sentences into paragraphs, used a bigger font for the formula to make it easier to read the superscript, replace <= with ≤.)
m (→‎{{header|REXX}}: added/changed comments and whitespace, optimized the code (for speed), made the code simplier.)
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if nn=='' | nn=="," then nn=10 /*Not specified? Then use the default.*/
if nn=='' | nn=="," then nn=10 /*Not specified? Then use the default.*/
N=abs(nn) /*N is the number of rows in triangle.*/
N=abs(nn) /*N is the number of rows in triangle.*/
@.=1; $.=@. /*default value for rows and for lines.*/
w=length( !(N-1) / !(N%2) / !(N-1-N%2) ) /*W: the width of the biggest integer.*/
w=length(!(N-1) / !(N%2) / !(N-1-N%2)) /*W is the width of the biggest number*/
@.=1; $.=@.; unity=right(1, w) /*defaults rows & lines; aligned unity.*/
/* [↓] build rows of Pascals' triangle*/
/* [↓] build rows of Pascals' triangle*/
do r=1 for N; rm=r-1 /*Note: the first column is always 1.*/
do r=1 for N; rm=r-1 /*Note: the first column is always 1.*/
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$.r = $.r right(@.r.c, w) /*and construct a line for output (row)*/
$.r = $.r right(@.r.c, w) /*and construct a line for output (row)*/
end /*c*/ /* [↑] C is the column being built.*/
end /*c*/ /* [↑] C is the column being built.*/
if r\==1 then $.r=$.r right(1, w) /*for most rows, append a trailing "1".*/
if r\==1 then $.r=$.r unity /*for rows≥2, append a trailing "1".*/
end /*r*/ /* [↑] R is the row being built.*/
end /*r*/ /* [↑] R is the row being built.*/
/* [↑] WIDTH: for nicely looking line.*/
/* [↑] WIDTH: for nicely looking line.*/
width=length($.N) /*width of the last (output) line (row)*/
width=length($.N) /*width of the last (output) line (row)*/
/*if NN<0, output is written to a file.*/
/*if NN<0, output is written to a file.*/
do r=1 for N /*show│write lines (rows) of triangle. */
do r=1 for N; $$=center($.r, width) /*center this particular Pascals' row. */
if nn>0 then say center($.r, width) /*SAY if NN positive,*/
if nn>0 then say $$ /*SAY if NN is positive, else */
else call lineout 'PASCALS.'n, center($.r, width) /*write──►file if not.*/
else call lineout 'PASCALS.'n, $$ /*write this Pascal's row ───► a file.*/
end /*r*/
end /*r*/
exit /*stick a fork in it, we're all done. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
!: procedure; parse arg x; !=1; do j=2 to x; !=!*j; end /*j*/; return !</lang>
!: procedure; !=1; do j=2 to arg(1); !=!*j; end /*j*/; return ! /*compute factorial*/</lang>
'''output''' &nbsp; when using the input of: &nbsp; <tt> 11 </tt>
'''output''' &nbsp; when using the input of: &nbsp; <tt> 11 </tt>
<pre>
<pre>
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