Source code in the rexx programming language

/*REXX program  obtains and displays  Catalan numbers  from  a  Pascal's triangle.      */
parse arg N .                                    /*Obtain the optional argument from CL.*/
if N=='' | N==","  then N=15                     /*Not specified?  Then use the default.*/
numeric digits max(9, N%2 + N%8)                 /*so we can handle huge Catalan numbers*/
@.=0;   @.1=1                                    /*stem array default; define 1st value.*/

  do i=1  for N;                               ip=i+1
                      do j=i   by -1  for N;   jm=j-1;   @.j=@.j+@.jm;    end /*j*/
  @.ip=@.i;           do k=ip  by -1  for N;   km=k-1;   @.k=@.k+@.km;    end /*k*/
  say  @.ip - @.i                                /*display the   Ith   Catalan number.  */
  end   /*i*/                                    /*stick a fork in it,  we're all done. */


/*REXX program  obtains and displays  Catalan numbers  from  a  Pascal's triangle.      */
parse arg N .                                    /*Obtain the optional argument from CL.*/
if N=='' | N==","  then N=15                     /*Not specified?  Then use the default.*/
numeric digits max(9, N%2 + N%8)                 /*so we can handle huge Catalan numbers*/
@.=0;  @.1=1                                     /*stem array default; define 1st value.*/
               do i=1  for N;  ip=i+1
                                      do j=i   by -1  for N;  @.j=@.j+@(j-1);   end  /*j*/
               @.ip=@.i;              do k=ip  by -1  for N;  @.k=@.k+@(k-1);   end  /*k*/
               say  @.ip - @.i                   /*display the   Ith   Catalan number.  */
               end   /*i*/
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
@:  parse arg !;   return @.!                    /*return the value of   @.[arg(1)]     */


/*REXX program  obtains and displays  Catalan numbers  from  a  Pascal's triangle.      */
parse arg N .                                    /*Obtain the optional argument from CL.*/
if N=='' | N==","  then N=15                     /*Not specified?  Then use the default.*/
numeric digits max(9, N%2 + N%8)                 /*so we can handle huge Catalan numbers*/
                      do j=1  for N              /* [↓]  display   N   Catalan numbers. */
                      say  comb(j+j, j) % (j+1)  /*display the   Jth   Catalan number.  */
                      end   /*j*/
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
!:    procedure; parse arg z;   _=1;     do j=1  for arg(1);  _=_*j;  end;        return _
/*──────────────────────────────────────────────────────────────────────────────────────*/
comb: procedure; parse arg x,y;        if x=y  then return 1;   if y>x  then return 0
      if x-y


/*REXX program  obtains and displays  Catalan numbers  from  a  Pascal's triangle.      */
parse arg N .                                    /*Obtain the optional argument from CL.*/
if N=='' | N==","  then N=15                     /*Not specified?  Then use the default.*/
numeric digits max(9, N%2 + N%8)                 /*so we can handle huge Catalan numbers*/
!.=.
                      do j=1  for N              /* [↓]  display   N   Catalan numbers. */
                      say  comb(j+j, j) % (j+1)  /*display the   Jth   Catalan number.  */
                      end   /*j*/
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
!:    procedure expose !.;  parse arg z;     if !.z\==. then return !.z;  _=1
                         do j=1  for arg(1);   _=_*j;   end;        !.z=_;   return _
/*──────────────────────────────────────────────────────────────────────────────────────*/
comb: procedure expose !.;  parse arg x,y;   if x=y  then return 1;  if y>x  then return 0
      if x-y