Velocity Reviews - evaluate a arithmetic expression

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evaluate a arithmetic expression

Hi,
I have written a code in evaluating a arithmetic expression.
Please review and suggest a better implementation.
Any comments are welcome.
The code: -
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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");
}

}

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Thanks
Pradyut
http://www.pradyut.co.nr/
India