Convert infix to Postfix

السلام عليكم

عندي مشكلة في هذا الكود

وهو إنه يحول من Infix إلى Postfix

طبعا هذا مثال على Input

http://www.m5zn.com/img/?img=1c7802ea56d005d.png

المشكلة عندي هي عندما أضع أقواس

مثلا

http://www.m5zn.com/img/?img=da5b98c6fdd065c.png

فإن الناتج يكون خاطئ

يستدعي error Method

وهذا كودي

  


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class SyntaxDirectedTranslantion {

    public static void main(String[] args) throws IOException {
        SyntaxDirectedTranslantion objectSysntax = new SyntaxDirectedTranslantion();
        objectSysntax.mainMethod();                               //Calls the function expr()
    }
    int lookahead;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public void mainMethod() throws IOException //main function
    {

        lookahead = br.read();

        expr();                               //Calls the function expr()
        if ((char) lookahead == '$') //Checks to see if the entire input has been read
        {
            System.out.print("\n Postfix form is as above:");
            //To wait for the user to read the message
        } else {
            error();
        }
    }

    public void expr() throws IOException {
        term();
        exprprime();

    }

    public void exprprime() throws IOException {
        if ((char) lookahead == '+') {
            match('+');
            term();
            System.out.print('+');
            exprprime();
        } else if ((char) lookahead == '-') {
            match('-');
            term();
            System.out.print('-');
            exprprime();
        } else;     //Null statement for ^-production in the grammar
    }

    private void term() throws IOException {
        factor();
        termprime();
    }

    private void factor() throws IOException {
        if (lookahead >= 48 && lookahead <= 57) {
            System.out.print((char) lookahead);
            match(lookahead);
            //  }
            // else {
            if ((char) lookahead == '(') {
                match('(');
                expr();
                match(')');
            }
        } else {
            error();
        }
    }

    private void termprime() throws IOException {
        if ((char) lookahead == '*') {
            match('*');
            term();
            System.out.print('*');
            termprime();
        } else if ((char) lookahead == '/') {
            match('/');
            term();
            System.out.print('/');
            termprime();
        }


    }

    private void match(int t) throws IOException {
        if (lookahead == t) {
            lookahead = (char) br.read();
        } else {
            System.out.println("ERROR");
            error();
        }

    }

    private void error() {
        System.out.print("\nSyntax Error....");
    }
}