adding cs235

cs235/lab04/ExpressionManagerInterface.h

@@ -0,0 +1,65 @@
+#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;
+
+
+};