The code better implemented: -
Please review and suggest a better implementation.
    Any comments are welcome.
    Download the code at: -
        http://myjavaserver.com/~pradyut/files/Calci.java
     The code: -
---------------------------------------------------------------------------------------------------------------------------------------------------------------------

public class Calci {

   
    public static void main(String[] args) {
      
        String a = "4-(6-1)+3*9/2(8(6-1))(7-43)4-(6-1)+3.67*9/2(8(6.77+1))(7-4.3)"; //1*3+2*7-1-1
        //(2+1)-(4-2)3/(-5)
        //3*(1-2)
        //4-(6-1)+3*9/2(8(6-1))(7-43)
        //14-(4/(6-9))
       
        String[] b = null;
        String c = null;
       
        Calci obj = new Calci();
       
        System.out.println(obj.parse(a));
       
    }
    double func(String a) {
        double d = 0;

        return d;
    }
    String mult(String a, String b) {
        double c = func1(a) * func1(b);
        return (Double.toString(c));
    }
    String minus(String a, String b) {

        double c = func1(a) - func1(b);
        System.out.println(c);
        return (Double.toString(c));
    }
    String add(String a, String b) {
        double c = func1(a) + func1(b);
        return (Double.toString(c));
    }

    String divide(String a, String b) {
        double c = func1(a) / func1(b);
        return (Double.toString(c));
    }

    double func1(String a) {
        double d =0;
        try {
            d = Double.parseDouble(a);
        } catch (NumberFormatException n1) {
            System.out.println(n1);
        }
        return d;
    }
   
   
    String parse(String a) {
        String b = null;
        String c = null, d= null, e=null;
        int z=0, f=0;
        if(a.contains("(")) {
           
           
            //System.out.println(b[0]);
           
            z = a.lastIndexOf("(");
            f = a.indexOf(")", z)+1;
            c = a.substring(z, f);
           
            b =a.substring(0, z);
            d = a.substring(f, a.length());
           
            //processing b
            if(b.length() >=1) {
                e = String.valueOf(b.charAt(b.length()-1));
                if(e.equals("+") || e.equals("-") || e.equals("*") || e.equals("/") || e.equals("(")) {

                }else
                {
                    b = b+ "*";
                }
                //System.out.println("b is: " + b);
            }
            //processing d
            if(d.length() >1) {
                e = String.valueOf(d.charAt(0));
                if(e.equals("+") || e.equals("-") || e.equals("*") || e.equals("/") || e.equals(")")) {

                }else
                {
                    d = "*" + d;
                }
                //System.out.println("d is: "+d);
            }
                c = check(brackets(c));
                //System.out.println("c is: "+c);
                //c = "5";
           
            a = b + c + d;
                if(a.contains("*-")) {
                    //System.out.println("inside a is: "+a);
                    z = a.indexOf("*-");
                    b = a.substring(0, z);
                    //System.out.println("inside b is: "+b);
                    a = a.substring(z, a.length());
                    b = repl(b);
                   
                    //System.out.println("inside a is: "+a);
                    a= a.replace("*-", "*");
                   
                    a = b+a;
                } else if (a.contains("--")) {
                    a= a.replace("--", "+");
                } else if (a.contains("+-")) {
                    a= a.replace("+-", "-");
                } else if (a.contains("/-")) {
                    z = a.indexOf("/-");
                    b = a.substring(0, z);
                    //System.out.println("inside b is: "+b);
                    a = a.substring(z, a.length());
                    /*if( b.lastIndexOf('+') > b.lastIndexOf('-'))
                        b=b.replace(b.charAt(b.lastIndexOf('+')), '-');
                    else
                        b=b.replace(b.charAt(b.lastIndexOf('-')), '+');
                    */
                    b=repl(b);
                    //System.out.println("inside a is: "+a);
                    a= a.replace("/-", "/");
                   
                    a = b+a;
                }
            System.out.println("a is: "+a);
                return parse(a);
           
            //System.out.println(a.substring(a.lastIndexOf("(")+1, a.indexOf(")", z)));
        }
        else
            return check(a);
    }
   
    String repl(String b) {
        int j,k,l;
        String h;
        if(b.length() >1)
        {
                if(b.contains("+") || b.contains("-")) {
                    j = b.lastIndexOf('+');
                    k = b.lastIndexOf('-');
                    l = b.lastIndexOf(')');
                    if (l<j || l<k) {
                        if( b.lastIndexOf('+') > b.lastIndexOf('-'))
                        {
                            System.out.println("inside");
                           
                            b=b.replace(b.charAt(b.lastIndexOf('+')), '-');
                            return b;
                        }
                        else
                        {
                            //System.out.println("test B");
                            System.out.println("inside 1");
                            b=b.replace(b.charAt(b.lastIndexOf('-')), '+');
                            return b;
                        }
                    } else {
                        System.out.println("inside 2");
                        h = b.substring(0, b.lastIndexOf('('));
                        System.out.println("h is: "+h);
                        b = b.substring(b.lastIndexOf('('), b.length());
                        System.out.println("b is: "+b);
                        if( h.lastIndexOf('+') > h.lastIndexOf('-'))
                        {
                            //System.out.println("test A");
                            h=h.replace(h.charAt(h.lastIndexOf('+')), '-');
                            b = h+b;
                            return b;
                        }
                        else
                        {
                            //System.out.println("test B");
                            h=h.replace(h.charAt(h.lastIndexOf('-')), '+');
                            b = h+ b;
                            return b;
                        }
                    }
                }
                else
                {
                    b = "-" + b;
                    return b;
                }
            } else
            {
                b = "-" + b;
                return b;
            }
    }
   
   
   
    String brackets(String b) {
        b = b.replace("(", "");
        b = b.replace(")", "");
        return b;
    }
   
    String check(String a) {
        String[] b=null;
       
        if(a.indexOf('+')==0) {
            a=a.substring(1);
            check(a);
        }
        if(a.contains("+")) {
            //System.out.println("This is inside minus");
           
           
            /*if(a.indexOf('+') ==0) {
                a=a.substring(1);
            }*/
            b = a.split("\\+",2);

            a=add(check1(b[0]),check(b[1])) ;
            return a;
        }
        else
            return check1(a);
    }

    private String check1(String a) {

        String[] b=null;
       
        if(a.contains("-")) {
           
           
            if(a.indexOf('-')==0)
            {
                a =a.substring(1);
                if(a.contains("-")) {
                    b = a.split("-", 2);
                    b[0] = "-" + b[0];
                    b[1] = "-" + b[1];
                    a = add(check2(b[0]), check1(b[1]));
                }
                else {
                    //System.out.println("this is here");
                    a = "-"+a;
                    a = check2(a);
                }
            } else {
                b = a.split("-", 2);
                //b[0] = "-" + b[0];

                b[1] = "-" + b[1];
                a = add(check2(b[0]), check1(b[1]));
            }
            return a;
        }else
            return check2(a);
        //throw new UnsupportedOperationException("Not yet implemented");

    }

    private String check2(String a) {
        String[] b=null;
        if(a.contains("*")) {
            b = a.split("\\*",2);
            a = mult(check3(b[0]), check2(b[1])) ;
            return a;
        }

        else
            return check3(a);
        //throw new UnsupportedOperationException("Not yet implemented");
    }

    private String check3(String a) {
        String[] b=null;
        if(a.contains("/")) {
            b = a.split("\\/");
            a = divide(b[0], check3(b[1])) ;
            return a;
        }

        else
            return a;
        //throw new UnsupportedOperationException("Not yet implemented");
    }

}

---------------------------------------------------------------------------------------------------------------------------------------------------------------------

Thanks




--
Pradyut
http://pradyut.tk
http://www.pradyut.co.nr/
http://oop-edge.blogspot.com/
http://pradyutb.blogspot.com/
http://praddy-photos.blogspot.com/
http://oop-edge.spaces.live.com/
http://groups.google.com/group/oop_programming
India

1. NIIT: Not Interested in IT

2. WIPRO: Weak Input, Poor & Rubbish Output

3. HCL: Hidden Costs & Losses

4. TCS : Totally Confusing Solutions

5. INFOSYS : Inferior Offline Systems

6. HUGHES : Highly Useless Graduates Hired for Eating and Sleeping

7. BAAN : Beggars Association and Nerds

8. IBM : Implicitly Boring Machines

9. SATYAM: Sad and Tired Yelling Away Madly

10. PARAM: Puzzled and Ridiculous Array of Microprocessors

11. C-DOT : Coffee during Office Timings

12. AT&T : All Troubles & Terrible

13. CMC : Coffee, Meals and Comfort

14. DEC : Drifting & Exhausted Computers

15. BFL : Brainwash first and Let them go

17. TISL : Totally Inconsistent Systems Ltd.

18. PSI : Peculiar Symptoms of India

19. ORACLE: On-line Romance And Chatting with Lady Employees .

20. PATNI : Pathetic Appraisal Techniques

--
Pradyut
http://pradyut.tk
http://oop-edge.blogspot.com/
http://pradyutb.blogspot.com/
http://praddy-photos.blogspot.com/
http://oop-edge.spaces.live.com/
http://www.flickr.com/photos/praddy
http://groups.google.com/group/oop_programming
India

--
Pradyut
http://pradyut.tk
http://oop-edge.blogspot.com/
http://pradyutb.blogspot.com/
http://praddy-photos.blogspot.com/
http://oop-edge.spaces.live.com/
http://www.flickr.com/photos/praddy
http://groups.google.com/group/oop_programming
India

--
Pradyut
http://pradyut.tk
http://oop-edge.blogspot.com/
http://pradyutb.blogspot.com/
http://praddy-photos.blogspot.com/
http://oop-edge.spaces.live.com/
http://www.flickr.com/photos/praddy
http://groups.google.com/group/oop_programming
India