Assembly language program to count number of vowels in a given string
Answers
Answer:
Explanation:
.MODEL SMALL
.STACK 100H
.DATA
PROMPT_1 DB 'Enter a string : $'
PROMPT_2 DB 0DH,0AH,'No. of Vowels = $'
PROMPT_3 DB 0DH,0AH,'No. of Consonants = $'
STRING DB 50 DUP (?)
C_VOWELS DB 'AEIOU'
S_VOWELS DB 'aeiou'
C_CONSONANTS DB 'BCDFGHJKLMNPQRSTVWXYZ'
S_CONSONANTS DB 'bcdfghjklmnpqrstvwxyz'
.CODE
MAIN PROC
MOV AX, @DATA ; initialize DS and ES
MOV DS, AX
MOV ES, AX
LEA DX, PROMPT_1 ; load and display the string PROMPT_1
MOV AH, 9
INT 21H
LEA DI, STRING ; set DI=offset address of variable STRING
CALL READ_STR ; call the procedure READ_STR
XOR DX, DX ; clear DX
LEA SI, STRING ; set SI=offset address of variable STRING
OR BX, BX ; check BX for 0
JE @EXIT ; jump to label @EXIT if BX=0
@COUNT: ; jump label
LODSB ; set AL=DS:SI
LEA DI, C_VOWELS ; set DI=offset address of variable C_VOWELS
MOV CX, 5 ; set CX=5
REPNE SCASB ; check AL is capital vowel or not
JE @INCREMENT_VOWELS ; jump to label @INCREMENT_VOWELS if AL is
; capital vowel
LEA DI, S_VOWELS ; set DI=offset address of variable S_VOWELS
MOV CX, 5 ; set CX=5
REPNE SCASB ; check AL is small vowel or not
JE @INCREMENT_VOWELS ; jump to label @INCREMENT_VOWELS if AL is
; small vowel
LEA DI, C_CONSONANTS ; set DI=offset address of variable
; C_CONSONANTS
MOV CX, 21 ; set CX=21
REPNE SCASB ; check AL is capital consonant or not
JE @INCREMENT_CONSONANTS ; jump to label @INCREMENT_CONSONANTS if AL
; is capital consonant
LEA DI, S_CONSONANTS ; set DI=offset address of variable
; S_CONSONANTS
MOV CX, 21 ; set CX=21
REPNE SCASB ; check AL is small consonant or not
JE @INCREMENT_CONSONANTS ; jump to label @INCREMENT_CONSONANTS if AL
; is small consonants
JMP @NEXT ; otherwise, jump to label @NEXT
@INCREMENT_VOWELS: ; jump label
INC DL ; increment DL
JMP @NEXT ; jump to label @NEXT
@INCREMENT_CONSONANTS: ; jump label
INC DH ; increment DH
@NEXT: ; jump label
DEC BX ; decrement BX
JNE @COUNT ; jump to label @COUNT while BX!=0
@EXIT: ; jump label
MOV CX, DX ; set CX=DX
LEA DX, PROMPT_2 ; load and display the string PROMPT_2
MOV AH, 9
INT 21H
XOR AX, AX ; clear AX
MOV AL, CL ; set AL=CL
CALL OUTDEC ; call the procedure OUTDEC
LEA DX, PROMPT_3 ; load and display the string PROMPT_3
MOV AH, 9
INT 21H
XOR AX, AX ; clear AX
MOV AL, CH ; set AL=CH
CALL OUTDEC ; call the procedure OUTDEC
MOV AH, 4CH ; return control to DOS
INT 21H
MAIN ENDP
;**************************************************************************;
;**************************************************************************;
;------------------------- Procedure Definitions ------------------------;
;**************************************************************************;
;**************************************************************************;
;**************************************************************************;
;------------------------------- READ_STR -------------------------------;
;**************************************************************************;
READ_STR PROC
; this procedure will read a string from user and store it
; input : DI=offset address of the string variabel
; output : BX=number of characters read
; : DI=offset address of the string variabel
PUSH AX ; push AX onto the STACK
PUSH DI ; push DI onto the STACK
CLD ; clear direction flag
XOR BX, BX ; clear BX
@INPUT_LOOP: ; loop label
MOV AH, 1 ; set input function
INT 21H ; read a character
CMP AL, 0DH ; compare AL with CR
JE @END_INPUT ; jump to label @END_INPUT if AL=CR
CMP AL, 08H ; compare AL with 08H
JNE @NOT_BACKSPACE ; jump to label @NOT_BACKSPACE if AL!=08H
CMP BX, 0 ; compare BX with 0
JE @INPUT_ERROR ; jump to label @INPUT_ERROR if BX=0
MOV AH, 2 ; set output function
MOV DL, 20H ; set DL=20H
INT 21H ; print a character
MOV DL, 08H ; set DL=08H
INT 21H ; print a character