23 lines
2.3 KiB
Rexx
23 lines
2.3 KiB
Rexx
/*REXX program sorts a (stemmed) array using a (stable) bubble─sort algorithm. */
|
|
call gen@ /*generate the array elements (strings)*/
|
|
call show 'before sort' /*show the before array elements. */
|
|
say copies('▒', 50) /*show a separator line between shows. */
|
|
call bubbleSort # /*invoke the bubble sort. */
|
|
call show ' after sort' /*show the after array elements. */
|
|
exit 0 /*stick a fork in it, we're all done. */
|
|
/*──────────────────────────────────────────────────────────────────────────────────────*/
|
|
bubbleSort: procedure expose @.; parse arg n; m= n-1 /*N: number of array elements. */
|
|
do m=m for m by -1 until ok; ok= 1 /*keep sorting array until done.*/
|
|
do j=1 for m; k= j+1; if @.j<=@.k then iterate /*Not out─of─order?*/
|
|
_= @.j; @.j= @.k; @.k= _ ok= 0 /*swap 2 elements; flag as ¬done*/
|
|
end /*j*/
|
|
end /*m*/; return
|
|
/*──────────────────────────────────────────────────────────────────────────────────────*/
|
|
gen@: @.=; @.1 = 'UK London'
|
|
@.2 = 'US New York'
|
|
@.3 = 'US Birmingham'
|
|
@.4 = 'UK Birmingham'
|
|
do #=1 while @.#\=='' /*determine how many entries in list. */
|
|
end /*#*/; #= # - 1; return /*adjust for the DO loop index; return*/
|
|
/*──────────────────────────────────────────────────────────────────────────────────────*/
|
|
show: do j=1 for #; say ' element' right(j,length(#)) arg(1)":" @.j; end; return
|