nombres

fill map
if (interchange == false)
map [startx][starty] = 's'
					= 'e'
else
map [startx][starty] = 'e'
map [starty][endy] = 'S'

-------------
boolean interchange false;
if (startX < end X || starrt Y > endY)
int auxX, auxY

auxX = startX
startX= endX
endX = auxX

auxY = startY
startY = endY
endY = auxY