school/cs235/lab04/ExpressionManagerInterface.h
2016-04-06 20:46:10 -07:00

66 lines
2.1 KiB
C++

#pragma once
#include <iostream>
#include <string>
#include <stack>
using namespace std;
class ExpressionManagerInterface
{
public:
ExpressionManagerInterface(){}
virtual ~ExpressionManagerInterface(){}
/*
* Checks whether an expression is balanced on its parentheses
*
* - The given expression will have a space between every number or operator
*
* @return true if expression is balanced
* @return false otherwise
*/
virtual bool isBalanced(string expression) = 0;
/**
* Converts a postfix expression into an infix expression
* and returns the infix expression.
*
* - The given postfix expression will have a space between every number or operator.
* - The returned infix expression must have a space between every number or operator.
* - Redundant parentheses are acceptable i.e. ( ( 3 * 4 ) + 5 ).
* - Check lab requirements for what will be considered invalid.
*
* return the string "invalid" if postfixExpression is not a valid postfix expression.
* otherwise, return the correct infix expression as a string.
*/
virtual string postfixToInfix(string postfixExpression) = 0;
/*
* Converts an infix expression into a postfix expression
* and returns the postfix expression
*
* - The given infix expression will have a space between every number or operator.
* - The returned postfix expression must have a space between every number or operator.
* - Check lab requirements for what will be considered invalid.
*
* return the string "invalid" if infixExpression is not a valid infix expression.
* otherwise, return the correct postfix expression as a string.
*/
virtual string infixToPostfix(string infixExpression) = 0;
/*
* Evaluates a postfix expression returns the result as a string
*
* - The given postfix expression will have a space between every number or operator.
* - Check lab requirements for what will be considered invalid.
*
* return the string "invalid" if postfixExpression is not a valid postfix Expression
* otherwise, return the correct evaluation as a string
*/
virtual string postfixEvaluate(string postfixExpression) = 0;
};