Solution:
1.Function toPostfix() now returns stack instead of vector, as now the postfix expression is added to the stack eg, [34,57.+] etc.
2.Edited the code for storing all the digits to the stack by traversing the string till we have a number.(see code till line no 29)
import java.util.Stack;
import java.util.Vector;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author Sandeep
*/
public class Main {
static Stack stack=new Stack();
static Stack stackT=new Stack();
//static Vector v=new Vector();
//static StringBuffer p=new StringBuffer();
public static Stack toPostfix(String q)
{
for(int i=0;i<q.length();i++)
{
if(q.charAt(i)=='0'||q.charAt(i)=='1'||q.charAt(i)=='2'||q.charAt(i)=='3'||q.charAt(i)=='4'||q.charAt(i)=='5'||q.charAt(i)=='6'||q.charAt(i)=='7'||q.charAt(i)=='8'||q.charAt(i)=='9')
{
StringBuffer p=new StringBuffer();
while(q.charAt(i)=='0'||q.charAt(i)=='1'||q.charAt(i)=='2'||q.charAt(i)=='3'||q.charAt(i)=='4'||q.charAt(i)=='5'||q.charAt(i)=='6'||q.charAt(i)=='7'||q.charAt(i)=='8'||q.charAt(i)=='9')
p.append(q.charAt(i++));
stackT.push(p);
i--;
}
else if(q.charAt(i)=='(')
{
stack.push(q.charAt(i));
}
else if(q.charAt(i)==')')
{
for(int j=0;!stack.empty()&&!stack.peek().equals('(');j++)
{
stackT.push(stack.pop().toString());
}
stack.pop();
}
else if(q.charAt(i)=='+'||q.charAt(i)=='-'||q.charAt(i)=='/'||q.charAt(i)=='*')
{
if(stack.empty()||stack.peek().equals('('))
stack.push(q.charAt(i));
else
{
while(!stack.empty()&&!stack.peek().equals('(')&&isHigh(q.charAt(i), stack.peek()))
{
stackT.push(stack.pop().toString());
}
stack.push(q.charAt(i));
}
}
}
while(!stack.empty())
{
stackT.push(stack.pop().toString());
}
System.out.println(stackT);
return stackT;
}
//problem lies here
public static boolean isHigh(char op, Object AtStack)
{
char opAtStack=AtStack.toString().charAt(0);
boolean isHigh=false;
if((op==opAtStack))
isHigh=true;
if((op=='+'||op=='-')&&(opAtStack=='/'||opAtStack=='*'))
{
isHigh=true;
}
if((op=='+'&&opAtStack=='-')||(op=='-'&&opAtStack=='+')||(op=='/'&&opAtStack=='*')||(op=='*'&&opAtStack=='/'))
{
isHigh=true;
}
return isHigh;
}
public static double result(Stack p)
{
for(int i=0;i<p.size();i++)
{
if(p.get(i).toString().startsWith("0")||p.get(i).toString().startsWith("1")||p.get(i).toString().startsWith("2")||p.get(i).toString().startsWith("3")||p.get(i).toString().startsWith("4")||p.get(i).toString().startsWith("5")||p.get(i).toString().startsWith("6")||p.get(i).toString().startsWith("7")||p.get(i).toString().startsWith("8")||p.get(i).toString().startsWith("9"))
{
stack.push(p.get(i));
}
if(p.get(i).toString().equals("+")||p.get(i).toString().equals("-")||p.get(i).toString().equals("/")||p.get(i).toString().equals("*"))
{
double a=Double.parseDouble(stack.pop().toString());
double b=Double.parseDouble(stack.pop().toString());
if(p.get(i).equals("+"))
{
stack.push(b+a);
}
else if(p.get(i).equals("-"))
{
stack.push(b-a);
}
else if(p.get(i).equals("/"))
{
stack.push(b/a);
}
else if(p.get(i).equals("*"))
{
stack.push(b*a);
}
}
}
System.out.println(stack);
return 0;
}
public static void main(String[] args) {
// TODO code application logic here
String s=new String("159*(79+23)-10/4+(22*54-67*(25*58))");
Main.result(Main.toPostfix(s));
System.out.println(159*(79+23)-10/4+(22*54-67*(25*58)));
}
}