Good day ^^
I want to create a program using tasm that will tell if the inputted string is a palindrome or not....but i don't know how will i get the first and last char to compare..unlike in C..i can use the strlen....XD
Please make the codes very simple ^^..tnx in advance XD
Whole codes? Well hint's are okay, but I won't cause fuss and try to figure out a completely running programme.
Think about how you determine the length of a string? Null-terminated? Fine.
I'd start like that:
Run through the string, till \0 comes. Decrease the register (let's call it the backcounter). Now run a second loop till the \0-character. Now compare the character of your backcounter with the one of your forward-counter. After each step you're decreasing the backcounter and increase the forward-counter.
That should be all.
Hope it helps.
You could start out with getting the user input of the word and then figure out the word length based on the left-over terminators.
Start with something like this:
http://www.daniweb.com/software-development/assembly/code/270832
...then count the characters based on the start position until you run into a terminator.
After that, you can copy and reverse the word and compare it.
Actually I know what should i do to tell if it is palindrome or not.. I already done it in turbo c but my problem is what is the equivalent code of strlen (to get the number of char) of tc in TASM..... i dont know how to get each character in tasm that is my only problem...XD
[Just getting string length]
Assuming a 10-char max string and a specific location,
this code compares the target string against a string of terminating dollar-signs.
;This determines a string length by
; producing a reverse count and subtracting
mov cx, 10 ; Max string length
mov dx, 9 ; one less than max (offset for $)
mov si, string1
mov di, string2
repne cmpsb
sub dx, cx ; Actual string length in DX
int 20h
string1: db 'One$$$$$$$'
string2: db '$$$$$$$$$$'Thanks for all the help...me and my two other classmates successfully finished the program ^^..XD
Great!
Here's what I hacked out (FYI):
;-------------------------------80x86----------------------------------------
; 8-Aug-2011 - THINES01
; Palindro.asm: to be compiled with A86 (http://eji.com/a86/)
; This program shows how to get user input with echo
; and test to see if it is a palindrome
; ---------------------------------------------------------------------------
mov dx, askString;
call doPrint
mov cx, 0ah
mov si, strOrig; ; Place to store the orig string
getString:
mov ah, 01h
int 21h ; Get input with echo
cmp al, 0dh ;
je printQuit ; Quit if Carriage-return
mov [si], al ; Put entered char in orig string
cmp byte ptr [finalStop], 24h ; is 10th dollar-sign gone?
jne printQuit ; if so, buffer is full?, quit
inc si ; move the position
loop getString; ; Keep going (looping)
printQuit:
mov dx, youEntered ;
call doPrint ; Print the finished message
; ---------------------------------------------------------------------------
strLen:
mov cx, 0bh ; max string length (plus terminator)
mov dx, 0ah ; minus 1
mov si, strOrig ;
mov di, strComp ; All terminators
repne cmpsb ;
sub dx, cx ; dx now holds num chars to reverse
; ---------------------------------------------------------------------------
doReverseCopy:
mov cx, dx ; copy the length for the next op
mov si, strOrig ;
mov di, strDest ;
add di, cx ;
dec di ; minus 1
reverseCopy:
mov bl, byte ptr [si] ; copy the chars from source
mov byte ptr[di], bl ; paste chars at destination
inc si ; next char forward
dec di ; next char backward
loop reverseCopy
; ---------------------------------------------------------------------------
compareStrings:
mov cx, 0ah ; max string length
mov si, strOrig ; Original string
mov di, strDest ; Compare string
repe cmpsb ;
cmp cx, 0h ;
jnz noMatch
; ---------------------------------------------------------------------------
isMatch:
mov dx, strIsMatch
call doPrint
jmp quit
strIsMatch: db 0ah, 0dh,'IS a palindrome!', 0ah, 0dh, 024h
; ---------------------------------------------------------------------------
noMatch:
mov dx, strNoMatch ; Display mismatch message
call doPrint
jmp quit
strNoMatch: db 0ah, 0dh,'NOT a palindrome!', 0ah, 0dh, 024h
; ---------------------------------------------------------------------------
doPrint:
mov ah, 09h
int 21h
ret
; ---------------------------------------------------------------------------
quit: int 20h ; *** DROP TO DOS ***
; ---------------------------------------------------------------------------
askString: db 'Enter a string of up to 10 characters: $'
youEntered: db 0ah, 0dh, 'You entered: '
strOrig: db '$$$$$$$$$$'
finalStop: db '$$'
strDest: db '$$$$$$$$$$$'
strComp: db '$$$$$$$$$$$'Great!
Here's what I hacked out (FYI):;-------------------------------80x86---------------------------------------- ; 8-Aug-2011 - THINES01 ; Palindro.asm: to be compiled with A86 (http://eji.com/a86/) ; This program shows how to get user input with echo ; and test to see if it is a palindrome ; --------------------------------------------------------------------------- mov dx, askString; call doPrint mov cx, 0ah mov si, strOrig; ; Place to store the orig string getString: mov ah, 01h int 21h ; Get input with echo cmp al, 0dh ; je printQuit ; Quit if Carriage-return mov [si], al ; Put entered char in orig string cmp byte ptr [finalStop], 24h ; is 10th dollar-sign gone? jne printQuit ; if so, buffer is full?, quit inc si ; move the position loop getString; ; Keep going (looping) printQuit: mov dx, youEntered ; call doPrint ; Print the finished message ; --------------------------------------------------------------------------- strLen: mov cx, 0bh ; max string length (plus terminator) mov dx, 0ah ; minus 1 mov si, strOrig ; mov di, strComp ; All terminators repne cmpsb ; sub dx, cx ; dx now holds num chars to reverse ; --------------------------------------------------------------------------- doReverseCopy: mov cx, dx ; copy the length for the next op mov si, strOrig ; mov di, strDest ; add di, cx ; dec di ; minus 1 reverseCopy: mov bl, byte ptr [si] ; copy the chars from source mov byte ptr[di], bl ; paste chars at destination inc si ; next char forward dec di ; next char backward loop reverseCopy ; --------------------------------------------------------------------------- compareStrings: mov cx, 0ah ; max string length mov si, strOrig ; Original string mov di, strDest ; Compare string repe cmpsb ; cmp cx, 0h ; jnz noMatch ; --------------------------------------------------------------------------- isMatch: mov dx, strIsMatch call doPrint jmp quit strIsMatch: db 0ah, 0dh,'IS a palindrome!', 0ah, 0dh, 024h ; --------------------------------------------------------------------------- noMatch: mov dx, strNoMatch ; Display mismatch message call doPrint jmp quit strNoMatch: db 0ah, 0dh,'NOT a palindrome!', 0ah, 0dh, 024h ; --------------------------------------------------------------------------- doPrint: mov ah, 09h int 21h ret ; --------------------------------------------------------------------------- quit: int 20h ; *** DROP TO DOS *** ; --------------------------------------------------------------------------- askString: db 'Enter a string of up to 10 characters: $' youEntered: db 0ah, 0dh, 'You entered: ' strOrig: db '$$$$$$$$$$' finalStop: db '$$' strDest: db '$$$$$$$$$$$' strComp: db '$$$$$$$$$$$'
thanks a lot thines01 hehehe your code is shorter than ours ^^
hi thines why is it unexpected end of file encountered?
i included .model small
.stack
.code
org 100h
start:
at the beginning of ur code
hi thines why is it unexpected end of file encountered?
i included .model small
.stack
.code
org 100h
start:
at the beginning of ur code
Maybe your compiler also needs the .model.
yah i included .model small
i got the same error: unexpected end of file encountered
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