//Implementation File

#include <iostream>
#include <string>
#include "myStack.h"
#include "infixToPostfix.h"

using namespace std;

void infixToPostfix::convertToPostfix()
{
	stackType<char>  oprStack;
	int i;
	char sOpr;

	i = 0;

	pfx = "";

	while (ifx[i] != ';')
	{
		ifx[i] = ifx[i+1];	
		switch (ifx[i])
		{
			case 'A':
			case 'B':
			case 'C':
			case 'D':
			case 'F':
			case 'G':
				pfx += ifx[i++];
				break;
			case ' ':
				break;
			case '^':
				oprStack.push(ifx[i]);
				break;
			case '+':
			case '-':
			case '*':
			case '/':
				while (!oprStack.isEmptyStack() && !precedence(ifx[i], oprStack.top()))
				{
					pfx += oprStack.top();
					oprStack.pop();
				}//end while
				oprStack.push(ifx[i]);
				break;
			case '(':  
				oprStack.push(ifx[i]);
				break;
			case ')':   
				sOpr = oprStack.top();
				oprStack.pop();
				while(sOpr != '(')
				{
					pfx += sOpr;
					if(!oprStack.isEmptyStack())
					{
						sOpr = oprStack.top();
						oprStack.pop();
					}
				}//end while
				break;
			default:
				break;						
		}//end switch
}//end while

	while (!oprStack.isEmptyStack())
	{
		sOpr = oprStack.top();
		pfx += sOpr;
	}//end while
}//end convertToPostfix


bool infixToPostfix::precedence(char opr1, char opr2)
{
	int prec1, prec2;

	if(opr1 == '*' || opr1 =='/')
		prec1 = 2;
	else
		if(opr1 == '+' || opr1 == '-')
			prec1 = 1;
		else
			if(opr1 ='(')
				prec1 = 0;

	if(opr2 == '*' || opr2 == '/')
		prec2 = 2;
	else
		if(opr2 =='+' || opr2 == '-')
			prec2 = 1;

	return(prec1 >= prec2);
}//end precedence

void infixToPostfix::getInfix(string data)
{
	ifx = data;
	convertToPostfix();
}


void infixToPostfix::showInfix()
{
	cout<<"Infix: "<<ifx<<endl;
}


void infixToPostfix::showPostfix()
{
	cout<<"Postfix: "<<pfx<<endl;
}

infixToPostfix::infixToPostfix(string ifx)
{
	ifx = ifx;
	convertToPostfix();
}