calculates the second endpoint of a line from one endpoint and the midpoint

calculates the second endpoint of a line from one endpoint and the midpoint

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    do
`print "Midpoint of TS is (5,12), enter T and find S"
input "Midpoint-X coord:", mx
input "Midpoint-Y coord:", my
print
input "Endpoint-X coord:", x
input "Endpoint-Y coord:", y

ex = (2 * mx) + -x
ey = (2 * my) + -y

print "------------------"
print "1st Endpoint: ("+str$(x)+","+str$(y)+")"
print "Midpoint: ("+str$(mx)+","+str$(my)+")"
print "------------------"
print "New Endpoint: ("+str$(ex)+","+str$(ey)+")"
print ""
print "----------------------------------------"
print ""
loop