datasg	segment	para 'code'
msg1	db	'Enter acapital leter string: ',"$"
msg2 	db	'The result string is: ',"$"
strlist	label	byte    
max	db	20
len	db	?
buffer	db	20 dup(' ')
dolar	db	'$'
datasg	ends
codesg		segment	para 'code'
main	proc	far
	assume	ds:datasg,cs:codesg
	mov	ax,datasg
	mov	ds,ax
	mov	ah,6h
	mov	al,25
	mov	ch,0
	mov	cl,0
	mov	dh,24
	mov	dl,79
	mov	bh,7
	int	10h
	mov	ah,2h
	mov	dh,10
	mov	dl,30
	mov	bh,0
	int	10h
	lea	dx,msg1
	mov	ah,9h
	int	21h
	mov	ah,0ah
	lea	dx,strlist
	int	21h
	lea	bx,buffer
	mov	cl,len
	mov	ch,0
next:	mov	ah,[bx]	
	cmp	ah,41h
	jb	p1
	cmp	ah,5ah
	ja	p1
	xor	ah,00100000B
	mov	[bx],ah
p1:	inc	bx
	loop	next
	mov	ah,2h
	mov	dh,12
	mov	dl,30
	mov	bh,0
	int	10h
	mov	ah,0
	lea	dx,msg2
	mov	ah,9h
	int	21h
	lea	dx,buffer
	mov	ah,9h
	int	21h
	mov	ax,4c00h
	int	21h	
main	endp
codesg	ends
	end	main