\START82\
\COMMENT=Program file dated 12/04/95, 15:54
\NAME=CIRCLE
\FILE=CIRCLE.82P
ClrHome
10\->\S
Disp "(X-H)\^2\+(Y-K)\^2\=R\^2\"
Disp ""
Prompt H
Prompt K
Prompt R
"K+\sqrt\(R\^2\-(X-H)\^2\)"\->\\Y1\
"K-\sqrt\(R\^2\-(X-H)\^2\)"\->\\Y2\
Lbl 1
\(-)\S\->\Xmin
S\->\Xmax
\(-)\S\->\Ymin
S\->\Ymax
ZSquare
Line(H-R,K,H+R,K)
Line(H,K+R,H,K-R)
Pause 
ClrHome
Disp "(1)ZOOM IN"
Disp "(2)ZOOM OUT"
Disp "(3)QUIT"
Disp ""
Input "ENTER 1,2,3 ",C
If C=3
Goto 5
If C=1
Then
S/2\->\S
Else
S*2\->\S
End
Goto 1
Lbl 5
ClrHome
\STOP82\