// *********
// proj4.cpp
// *********

#include <iostream>
#include <string>
#include "infixPostfix.h"

using namespace std; 

int main()
{

	// input infix and postfix strings; 
	string infixExp, postfixExp;

	// object used for evaluating postfix expressions
	postfixEval pexp; 

	// object for evaluating infix conversions
	infixEval iexp;

	// object for conversion from infix to postfix
	infix2Postfix i2pexp;
	
	
        // postfix expression input
	cout << "Enter a postfix expression: "; 
	getline(cin, postfixExp); 

        while (postfixExp != ""){
            try{
	        // assign the expression to exp
	        pexp.setPostfixExp(postfixExp); 

	        // call evaluate() in a try block in case an error occurs
                cout << "The postfix expression " << pexp << " has value " 
		    << pexp.evaluate() << endl << endl; 
            }

	     catch (const expressionError& ee)
	     {
	         cout << ee.what() << endl << endl;
	     }

	    // input another expression
	    cout << "Enter another postfix expression: ";
	    getline(cin, postfixExp);
        }

	// input and evaluate infix expressions until the
	// user enters an empty string

	// get the first expression
	cout << "Enter an infix expression: ";
	getline(cin, infixExp);

	while (infixExp != "")
	{

            try
	    { 
		// an exception may occur. enclose the conversion
		// to postfix and the output of the expression
		// value in a try block

		iexp.setInfixExp(infixExp); 
		cout << "The infix expression is " << iexp << endl; 

		// convert to postfix
		i2pexp.setInfixExp(infixExp);
		postfixExp = i2pexp.postfix();

		// output the postfix expression
		cout << "Its postfix form is " << postfixExp << endl;
		cout << "It has value " << iexp.evaluate() << endl << endl;
	    }

            // catch an exception and output the error
	    catch (const expressionError& ee)
	    {
		cout << ee.what() << endl << endl;
	    }

	    // input another expression
	    cout << "Enter an infix expression: ";
	    getline(cin, infixExp);
   	}

        return 0; 
}