String operations(using menu) in 8086 Assembly Language(ALP)

Program Description

String operations in 8086 ALP using case structure(menu driven) This program demonstrates implementation of menu driven program using string operations such as calculating length of a string, counting number of spaces in a string,reversing a string,etc in 8086 Assembly language.

The program displays a menu to the user and performs action as per the user input.

; String operations(using menu) in 8086 Assembly Language(ALP)

;macro for printing a string
print macro m
mov ah,09h
mov dx,offset m
int 21h

.model small

;******  Data Segment ******

menu db 10,13, "Menu: "
     db 10,13, "1.Enter the string "
     db 10,13, "2.Count spaces "
     db 10,13, "3.Reverse "
     db 10,13, "4.Check for palindrome "
	 db 10,13, "5.Concatenate "
     db 10,13, "6.Exit  "
     db 10,13, "  "
     db 10,13, "Your choice: $"
msg1 db 10,13, "Your choice is: $"
mc1 db 10,13, "case 1 $"
mc2 db 10,13, "case 2 $"
mc3 db 10,13, "case 3 $"
mc4 db 10,13, "case 4 $"
mc5 db 10,13, "case 5 $"
mc6 db 10,13, "Exiting the program $"
mc7 db 10,13, "Invalid choice....try again $"
empty db 10,13, "   $"
str1 db 25,?,25 dup('$')
str2 db 25,?,25 dup('$')
len db ?
mstring db 10,13, "Enter the string: $"
notpalin db 10,13, "String is not a palindrome. $"
palin db 10,13, "String is a palindrome. $"
mstring2 db 10,13, "Enter second string: $"
mconcat db 10,13, "Concatenated string: $"
mscount db 10,13, "Number of spaces: $"
mlength db 10,13, "Length is: $"
mreverse db 10,13, "Reversed string: $"
scount db ?

;********** Code Segment ************


mov ax,@data
mov ds,ax


print menu
call accept  ;accept user choice
mov bl,al


        cmp bl,"1"    ;compare user choice with '1'
        jne case2     ;if not equal,check for case 2

        print mc1           
		print empty         
		print mstring
        call accept_string   ;function call to accept a string

        mov cl,str1+1        ;storing length in cl
        mov bl,cl             
		print mlength       
        call display1        ;printing the length
		print empty
        jmp again            ;printing the menu again

case2:  cmp bl,"2"         ;checking user choice for case 2
        jne case3          ;if not equal,check for case 3
        print mc2
		print empty
		print mstring
		call accept_string
        mov si,offset str1+2  ;position si to start of the string
		mov cl,str1+1         ;copy length in cl
        mov dh,00             ;counter to store number of spaces  
cmpagain1:  mov al,[si]      ;copy content at memory location "si" in "al"
		   cmp al,' '        ;compare "al" with space
           jne below         ;if not equal jump to label below
		   inc dh
below:  inc si               ;move to next character
        dec cl               ;decrement string length counter
        jnz cmpagain1        ;if not zero check again
		mov scount,dh       ;save the count in memory location "scount"
        mov bl,scount       ;copy count to "bl" for printing 
        print mscount
		call display1
        print empty		
        jmp again

case3:  cmp bl,"3"         ;checking user choice afor case 3
        jne case4          ;if not equal,check for case 4
        print mc3
		print empty
        print mstring
        call accept_string

        mov si,offset str1      ;point si to start of string1 
        mov di,offset str2      ;point di to start of string2

        mov al,[si]         ;copy first two locations of string1 to string2
        mov [di],al         ;since these contain the size and length of the string
        inc si              ;which are same in reverse string also
        inc di

        mov al,[si]
        mov [di],al
        inc si
        inc di

        mov cl,str1+1 ;        copy length in cl
        mov ch,00              
        add si,cx              ;add length of string1 to si to move it to last location
        dec si                 ;si at last location of string1
move_more: mov al,[si]       ;copying character one by one from string1 pointed by si
           mov [di],al       ; to string2 pointed by "di" in reverse order as si moves
           dec si            ; from last character to first character 
           inc di
           dec cl
           jnz move_more

		print mreverse
        print str2+2     ;  printing the reversed string
		print empty

        mov ah,00
        mov al,cl
        jmp again

case4:  cmp bl,"4"         ;checking for case 4
        jne case5          ;if not equal jump to case 5
        print mc4
		print empty
		print mstring
        call accept_string

        mov si,offset str1
		mov cl,str1+1        ;store the length
		mov ch,00h
		mov len,cl
		inc si
		add si,cx            ;si points to last
		mov di,offset str1   ;di to start of string
		add di,0002h         ;di to actual start of string;
		;in string 0th byte->size
		;          1st byte->length of string
        ;          from 2nd byte->actual string 		
		mov cl,len ;load counter
 cmpagain: mov al,[si]
           mov ah,[di]
		   inc di
		   dec si
           cmp al,ah
           jne nopalin
		   dec cl
		   jnz cmpagain
		print palin
		print empty
        jmp again		
nopalin: print notpalin		
		print empty
        jmp again

case5: cmp bl,"5"       ;check for case 5
       jne case6        ;if not equal check for case 6
       print mc5 
	   print empty
	   print mstring
	   call accept_string     
	   ;storing string in str2
	   print mstring2
	   mov ah,0ah
	   lea dx,str2
	   int 21h
	   mov cl,str1+1         ;length of string1 in cl
	   mov si,offset str1
next:  inc si
	   dec cl
	   jnz next
	   inc si
	   inc si
	   mov di,offset str2
	   inc di
	   inc di
	   mov cl,str2+1
	       mov al,[di]
	       mov [si],al
		   inc si
		   inc di
		   dec cl
		   jnz move_next
		   print mconcat
		   print str1+2
		   print empty	   
	   jmp again
case6: cmp bl,"6"     ;check for case 6
       jne case7      ;if not equal,default to case 7 and print the error message
	   print mc6
	   jmp exit
case7: print mc7   ;print error message
       jmp again   ;display the menu again

mov ah,4ch       ;exit the program
int 21h

;accept procedure

accept proc near

mov ah,01
int 21h
accept endp

display1 proc near

   mov al,bl
   mov bl,al
   and al,0f0h
   mov cl,04
   rol al,cl

   cmp al,09
   jbe number
   add al,07
number:  add al,30h
         mov dl,al
         mov ah,02
         int 21h

         mov al,bl
         and al,00fh
         cmp al,09
         jbe number2
         add al,07
number2:  add al,30h
          mov dl,al
          mov ah,02
          int 21h
display1 endp

accept_string proc near

mov ah,0ah          ;accept string from user function
mov dx,offset str1  ; store the string in memory pointed by "DX"
int 21h
accept_string endp

end start


Space Count


Palindrome(Test Case 1)

Palindrome(Test Case 2)


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