Check If A String Is Balanced (Different Types Of Brackets) Using Flat Assembler Assignment Solution

format PE console

entry _start

include 'win32a.inc'

header: DB "This program checks if the parentheses, brackets, and braces are balanced.", 10, 13, 0

prompt:      DB "Please enter a string: ", 10, 13, 0

balanced:      DB "This string is balanced.", 0

notbalanced:     DB "This string is not balanced.", 0

newline:      DB 10, 13, 0

string:      DB 100 DUP(?)

section '.text' code readable executable 

_start:

    push ebp

    mov ebp, esp

    ; print header message

    push header      ;load address of message

    call [printf]      ; print the string

    add esp, 4      ;restore stack

    ; prompt user to enter a string

    push prompt      ;load address of prompt

    call [printf]     ;print the string

    add esp, 4     ; restore stack

    ;read the string

    push [_iob]      ; pass stdin

    mov eax, 100     ; max string size

    push eax      ; pass max length

    push string     ; pass string address

    call [fgets]     ; read the string

    add esp, 12      ; restore stack

    ;check parentheses, brackets and braces

    mov esi, string     ; point to start of string

chkloop:

    mov al,[esi]      ; load character from string

    cmp al,13      ; if end of string

    je endloop

    cmp al, '('     ; if opening

    je pushOpen     ; push to stack

    cmp al, '['     ; if opening

    je pushOpen     ; push to stack

    cmp al, '{'      ; if opening

    je pushOpen     ; push to stack

    cmp al, ')'      ; if closing

    je checkParen     ; check parenthesis

    cmp al, ']'     ; if closing

    je checkBracket      ; check bracket

    cmp al, '}'     ; if closing

    je checkBrace     ; check brace

    jmp next     ; else advance to next

pushOpen:

    push eax     ; save opening character

    jmp next     ; continue to next char

checkParen:

    cmp esp, ebp      ; check if stack is empty

    je error     ; if empty, is an error

    pop eax      ; else, pop character

    cmp al, '('     ; check if is opening parenthesis

    jne error      ; if not, is not balanced

    jmp next      ; else, continue to next character

checkBracket:

    cmp esp, ebp     ; check if stack is empty

    je error     ; if empty, is an error

    pop eax      ; else, pop character

    cmp al, '['     ; check if is opening bracket

    jne error     ; if not, is not balanced

    jmp next     ; else, continue to next character

checkBrace:

    cmp esp, ebp      ; check if stack is empty

    je error     ; if empty, is an error

    pop eax     ; else, pop character

    cmp al, '{'     ; check if is opening brace

    jne error      ; if not, is not balanced

next:

    inc esi      ; advance to next character in string

    jmp chkloop      ; continue

    endloop:

    cmp esp, ebp      ; check if stack is empty

    jne error      ; if not empty, is an error

    ; Print the balanced result message:

    push balanced     ; load address of the balanced message

    call [printf]      ; print the string

    add esp, 4      ; restore stack

    jmp endprog      ; end program

    error: 

    ; print the not balanced message

    push notbalanced      ; load address of unbalanced message

    call [printf]      ; print message

    add esp, 4      ; restore stack

    endprog: 

    push newline     ; load address of newline

    call [printf]     ; print newline

    add esp, 4     ; restore stack

    call [getchar]     ; wait until user presses a key 

     mov esp, ebp

    pop ebp

    call [ExitProcess]     ; exit the program

   ; Import section  

section '.idata' import data readable

  library kernel32, 'kernel32.dll', \

        msvcrt,'msvcrt.dll'

import kernel32, \

       ExitProcess,'ExitProcess'

  import msvcrt, \

        printf, 'printf', fgets, 'fgets', \

        getchar, 'getchar', _iob, '_iob'