CMPS 223 Data Structures and Algorithms 
         Lab 4: Stack Implementations and Application 
		         Of Stack

I. Purposes:

   1. Statck implementation with Singly-Linked Structures

   2. Understand the Infix to Postfix conversion algorithm

   3. Understanding postfix arithmetic evaluation algrithm
 

II. What you are going to do:


    Work in one of four teams during the lab time. 

    1. Implmentation template class for stack ADT using singly-linked structure

    2. Implement a Expression class (not template class) with at least the following
       members:
		const int MAX_LEN = 501;

		class Expression {

		   private:
			char infExpr[MAX_LEN];   // holding infix arithmetic expr.
			char ** postExpr;        // a pointer to pointer arrays
						 // elements of which points at
						 // tokens of expr in postfix notation.
			int value;   // result of infix expr. evaluated from postExpr,
				     // postExpr is converted from infix expr.
			bool done;		// already converted and evaluated.
			...
		   public:
			void 
			setInfix( const * in );
			const char * toPost(); // convert if necessary, and output
					       // postfix notation of correspoinding
					       // infix expr.
		};

    3. Design and implement a driver program to test application of 
       infix-postfix-evaluation.