function?astardemo
%ASTARDEMO?Demonstration?of?ASTAR?algorithm

n?=?20;???%?field?size?n?x?n?tiles
wallpercent?=?0.45;??%?this?percent?of?field?is?walls

%?create?the?n?x?n?FIELD?with?wallpercent?walls?containing?movement?costs?
%?a?starting?position?STARTPOSIND?a?goal?position?GOALPOSIND?the?costs?
%?A?star?will?compute?movement?cost?for?each?tile?COSTCHART?
%?and?a?matrix?in?which?to?store?the?pointers?FIELDPOINTERS
[field?startposind?goalposind?costchart?fieldpointers]?=?...
??initializeField（nwallpercent）;

%?initialize?the?OPEN?and?CLOSED?sets?and?their?costs
setOpen?=?[startposind];?setOpenCosts?=?[0];?setOpenHeuristics?=?[Inf];
setClosed?=?[];?setClosedCosts?=?[];
movementdirections?=?{‘R‘‘L‘‘D‘‘U‘};

%?keep?track?of?the?number?of?iterations?to?exit?gracefully?if?no?solution
counterIterations?=?1;

%?create?figure?so?we?can?witness?the?magic
axishandle?=?createFigure（fieldcostchartstartposindgoalposind）;

%?as?long?as?we?have?not?found?the?goal?or?run?out?of?spaces?to?explore
while?~max（ismember（setOpengoalposind））?&&?~isempty（setOpen）
??%?for?the?element?in?OPEN?with?the?smallest?cost
??[temp?ii]?=?min（setOpenCosts?+?setOpenHeuristics）;
??%?find?costs?and?heuristic?of?moving?to?neighbor?spaces?to?goal
??%?in?order?‘R‘‘L‘‘D‘‘U‘
??[costsheuristicsposinds]?=?findFValue（setOpen（ii）setOpenCosts（ii）?...
????fieldgoalposind‘euclidean‘）;
??%?put?node?in?CLOSED?and?record?its?cost
??setClosed?=?[setClosed;?setOpen（ii）];
??setClosedCosts?=?[setClosedCosts;?setOpenCosts（ii）];
??%?update?OPEN?and?their?associated?costs
??if?（ii?>?1?&&?ii?????setOpen?=?[setOpen（1:ii-1）;?setOpen（ii+1:end）];
????setOpenCosts?=?[setOpenCosts（1:ii-1）;?setOpenCosts（ii+1:end）];
????setOpenHeuristics?=?[setOpenHeuristics（1:ii-1）;?setOpenHeuristics（ii+1:end）];
??elseif?（ii?==?1）
????setOpen?=?setOpen（2:end）;
????setOpenCosts?=?setOpenCosts（2:end）;
????setOpenHeuristics?=?setOpenHeuristics（2:end）;
??else
????setOpen?=?setOpen（1:end-1）;
????setOpenCosts?=?setOpenCosts（1:end-1）;
????setOpenHeuristics?=?setOpenHeuristics（1:end-1）;
??end
??%?for?each?of?these?neighbor?spaces?assign?costs?and?pointers;?
??%?and?if?some?are?in?the?CLOSED?set?and?their?costs?are?smaller?
??%?update?their?costs?and?pointers
??for?jj=1:length（posinds）
????%?if?cost?infinite?then?it‘s?a?wall?so?ignore
????if?~isinf（costs（jj））
??????%?if?node?is?not?in?OPEN?or?CLOSED?then?insert?into?costchart?and?
??????%?movement?pointers?and?put?node?in?OPEN
??????if?~max（[setClosed;?setOpen]?==?posinds（jj））
????????fieldpointers（posinds（jj））?=?movementdirections（jj）;
????????costchart（posinds（jj））?=?costs（jj）;
????????setOpen?=?[setOpen;?posinds（jj）];
????????setOpenCosts?=?[setOpenCosts;?costs（jj）];
????????setOpenHeuristics?=?[setOpenHeuristics;?heuristics（jj）];
??????%?else?node?has?already?been?seen?so?check?to?see?if?we?have
??????%?found?a?better?route?to?it.
??????elseif?max（setOpen?==?posinds（jj））
????????I?=?find（setOpen?==?posinds（jj））;
????????%?update?if?