Infix_to_Postfix

package main;
import java.util.*;

public class infix_postfix {
	String InPost(String f) {
		// infix to postfix -> done using stack
		String output="";
		String s = "";
		Stack<String> op = new Stack<String>();
		char c;
		String fix=f;
		String pf = "";
		for(int i = 0; i<fix.length(); i++) {
			c = fix.charAt(i);
			if(c!='+'&&c!='-'&&c!='%'&&c!='*'&&c!='/'&&c!='('&&c!=')'&&c!=' ') {
				System.out.println("In if : "+c);
				pf = pf + c;
			}
//			else if(c == 6367022399 )
			else if(c=='+'||c=='-'||c=='%'||c=='*'||c=='/'||c=='(') {
				op.push(c+"");
				System.out.println("Stack : "+c);
			}
			else if(c==')') {
				// jab bhi / aata hai, we remove the operator is stack along with ( --- always
				System.out.println(" ");
				System.out.println(":Stack Now is :::::::::::::::: "+op);				
				s = op.pop();
				op.pop();		// for popping ( with every operator
				System.out.println("Exiting : "+s);
				if(!s.equals("(")){
					output = output +pf+s;
				}
				pf = "";
			}
			
		}
		return output;
	}

	public static void main(String[] args) {
		infix_postfix a = new infix_postfix();
//		String res = a.InPost("((a-b)*((m+n)/(p+q)))");
		String res = a.InPost("((a+b) * (c-d))");
		System.out.println("Result is : "+res);
	}

}