Home / Assembly Language Programming / An Assembly Language Program that prompts a user to enter a line of text. On the next line, display the capital letter entered that comes first alphabetically and the one that comes last, If no capital letters are entered, display “No Capital Letters”

An Assembly Language Program that prompts a user to enter a line of text. On the next line, display the capital letter entered that comes first alphabetically and the one that comes last, If no capital letters are entered, display “No Capital Letters”

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An Assembly Language Program that prompts a user to enter a line of text. On the next line, display the capital letter entered that comes first alphabetically and the one that comes last, If no capital letters are entered, display “No Capital Letters” .

 .MODEL SMALL
 .STACK 100H

 .DATA
   PROMPT_1  DB  'Enter a line of text : $'
   PROMPT_2  DB  0DH,0AH,'First Capital Letter : $'
   PROMPT_3  DB  0DH,0AH,'Last Capital Letter  : $'
   PROMPT_4  DB  0DH,0AH,' *****  No Capital Letters  *****$'

   FLAG          DB  0
   FIRST_LETTER  DB  5BH
   LAST_LETTER   DB  40H

 .CODE
   MAIN PROC
     MOV AX, @DATA                ; initialize DS
     MOV DS, AX

     LEA DX, PROMPT_1             ; load and display the string PROMPT_1
     MOV AH, 9
     INT 21H

     MOV AH, 1                    ; set input function

     @INPUT:                      ; jump label
       INT 21H                    ; read a character

       MOV BL, AL                 ; set BL=AL

       CMP BL, 0DH                ; compare BL with CR
       JE @END_INPUT              ; jump to label @END_INPUT if BL=CR

       CMP BL, "A"                ; compare BL with "A"
       JL @INPUT                  ; jump to label @INPUT if BL<A

       MOV FLAG, 1                ; set FLAG=1

       CMP BL, "Z"                ; compare BL with "Z"
       JG @INPUT                  ; jump to label @INPUT if BL>Z

       CMP BL, FIRST_LETTER       ; compare BL with variable FIRST_LETTER
       JG @NEXT                   ; jump to label @NEXT if BL>FIRST_LETTER
       MOV FIRST_LETTER, BL       ; set FIRST_LETTER=BL

       @NEXT:                     ; jump label
         CMP BL, LAST_LETTER      ; compare BL with variable LAST_LETTER
         JL @INPUT                ; jump to label @INPUT if BL<LAST_LETTER
         MOV LAST_LETTER, BL      ; set LAST_LETTER=BL

     JMP @INPUT                   ; jump to label @INPUT

     @END_INPUT:                  ; jump label

     CMP FLAG, 1                  ; compare FLAG with 1             
     JE @DISPLAY                  ; jump to label @DISPLAY if FLAG=1

     LEA DX, PROMPT_4             ;  load and display the string PROMPT_4
     MOV AH, 9                    
     INT 21H

     JMP @END                     ; jump to label @END

     @DISPLAY:                    ; jump label
       LEA DX, PROMPT_2           ; load and display the string PROMPT_2
       MOV AH, 9                  
       INT 21H                    

       MOV AH, 2                  ; set output function
       MOV DL, FIRST_LETTER       ; set DL=FIRST_LETTER
       INT 21H                    ; print a character

       LEA DX, PROMPT_3           ; load and display the string PROMPT_3
       MOV AH, 9                  
       INT 21H                    

       MOV AH, 2                  ; set output function
       MOV DL, LAST_LETTER        ; set DL=LAST_LETTER
       INT 21H                    ; print a character

     @END:                        ; jump label

     MOV AH, 4CH                  ; return control to DOS
     INT 21H
   MAIN ENDP
 END MAIN

.MODEL SMALL

.STACK 100H

.DATA

PROMPT_1 DB 'Enter a line of text : $'

PROMPT_2 DB 0DH,0AH,'First Capital Letter : $'

PROMPT_3 DB 0DH,0AH,'Last Capital Letter : $'

PROMPT_4 DB 0DH,0AH,' ***** No Capital Letters *****$'

FLAG DB 0

FIRST_LETTER DB 5BH

LAST_LETTER DB 40H

.CODE

MAIN PROC

MOV AX, @DATA ; initialize DS

MOV DS, AX

LEA DX, PROMPT_1 ; load and display the string PROMPT_1

MOV AH, 9

INT 21H

MOV AH, 1 ; set input function

@INPUT: ; jump label

INT 21H ; read a character

MOV BL, AL ; set BL=AL

CMP BL, 0DH ; compare BL with CR

JE @END_INPUT ; jump to label @END_INPUT if BL=CR

CMP BL, "A" ; compare BL with "A"

JL @INPUT ; jump to label @INPUT if BL<A

MOV FLAG, 1 ; set FLAG=1

CMP BL, "Z" ; compare BL with "Z"

JG @INPUT ; jump to label @INPUT if BL>Z

CMP BL, FIRST_LETTER ; compare BL with variable FIRST_LETTER

JG @NEXT ; jump to label @NEXT if BL>FIRST_LETTER

MOV FIRST_LETTER, BL ; set FIRST_LETTER=BL

@NEXT: ; jump label

CMP BL, LAST_LETTER ; compare BL with variable LAST_LETTER

JL @INPUT ; jump to label @INPUT if BL<LAST_LETTER

MOV LAST_LETTER, BL ; set LAST_LETTER=BL

JMP @INPUT ; jump to label @INPUT

@END_INPUT: ; jump label

CMP FLAG, 1 ; compare FLAG with 1

JE @DISPLAY ; jump to label @DISPLAY if FLAG=1

LEA DX, PROMPT_4 ; load and display the string PROMPT_4

MOV AH, 9

INT 21H

JMP @END ; jump to label @END

@DISPLAY: ; jump label

LEA DX, PROMPT_2 ; load and display the string PROMPT_2

MOV AH, 9

INT 21H

MOV AH, 2 ; set output function

MOV DL, FIRST_LETTER ; set DL=FIRST_LETTER

INT 21H ; print a character

LEA DX, PROMPT_3 ; load and display the string PROMPT_3

MOV AH, 9

INT 21H

MOV AH, 2 ; set output function

MOV DL, LAST_LETTER ; set DL=LAST_LETTER

INT 21H ; print a character

@END: ; jump label

MOV AH, 4CH ; return control to DOS

INT 21H

MAIN ENDP

END MAIN

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An Assembly Language Program that prompts a user to enter a line of text. On the next line, display the capital letter entered that comes first alphabetically and the one that comes last, If no capital letters are entered, display “No Capital Letters”

An Assembly Language Program that prompts a user to enter a line of text. On the next line, display the capital letter entered that comes first alphabetically and the one that comes last, If no capital letters are entered, display “No Capital Letters” .

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