\START\
\COMMENT=Program file dated 08/06/95, 22:05
\NAME=Riem
\FILE=RIEM.85P

ClLCD
Disp " Riemann Integration"
Disp ""
Disp "Do you want graphics"
Menu(1,"Yes",YES,5,"No",NO)

Lbl YES
1\->\G
Disp "Graphics On"
Goto NINT

Lbl NO
0\->\G
Disp "No Graphics"

Lbl NINT
Prompt xMin
Prompt xMax

Lbl Opts
ClLCD
Disp "Number of intervals:"
Prompt N
(xMax-xMin)/N\->\D
Disp "Left or Right hand"
Menu(1,"Left",LEFT,5,"Right",RIGHT)

Lbl RIGHT
D\->\LR
Disp "Right"
Goto ChkG

Lbl LEFT
0\->\LR
Disp "Left"

Lbl ChkG
If G==0
	Goto NoG
	
ClDrw
If G==1
Then
	FnOff 
	FnOn 1
	fMax(y1,x,xMin,xMax)\->\V
	evalF(y1,x,V)\->\yMax
	fMin(y1,x,xMin,xMax)\->\V
	evalF(y1,x,V)\->\yMin
	(yMax-yMin)/62\->\H
	yMax+H\->\yMax
	yMin-H\->\yMin
	If yMin>0
		0\->\yMin
	If yMax<0
		0\->\yMax
	DrawF y1
	StPic functgr
	2\->\G
	FnOff
End

Lbl NoG
0\->\RSum
xMin\->\X
If G==2
	RcPic functgr
	
For(I,1,N,1)
	X+LR\->\x
	y1\->\Y
	If G==0
		Goto AddOn
	Line(X,0,X,Y)
	Line(X,Y,X+D,Y)
	Line(X+D,0,X+D,Y)

	Lbl AddOn
	RSum+Y\->\RSum
	X+D\->\X
End

If G\<>\0
	Pause
	
RSum*D\->\RSum
Disp "Riemann sum=",RSum
Menu(1,"Again",Opts,5,"Quit",Quit)

Lbl Quit
\STOP\