Name : Neeraj Gopal
Roll : 100070020
Lab batch : 16,Monday

The basic logic of the program to covert infix to postfix is as follows:

In normal algebra we use the infix notation like a+b*c. The corresponding postfix notation is abc*+. The algorithm for the conversion is as follows :

    * Scan the Infix string from left to right.
    * Initialise an empty stack.
    * If the scannned character is an operand, add it to the Postfix string. If the scanned character is an operator and if the stack is empty Push the character to stack.
          o If the scanned character is an Operand and the stack is not empty, compare the precedence of the character with the element on top of the stack (topStack). If topStack has higher precedence over the scanned character Pop the stack else Push the scanned character to stack. Repeat this step as long as stack is not empty and topStack has precedence over the character.
      Repeat this step till all the characters are scanned.
    * (After all characters are scanned, we have to add any character that the stack may have to the Postfix string.) If stack is not empty add topStack to Postfix string and Pop the stack. Repeat this step as long as stack is not empty.
    * Return the Postfix string.


A short summary of the work done last week is as follows:

Date : 23-10-10
Duration : 6:00pm - 8:30pm

	We met at the room of our team leader(siyar).We analysed the 1st phase of our programming.Our aim for the 1st submission was to convert the infix expression entered by the user to a postfix expression.We had downloaded a code which did the same and we analysed the code to try and understand the logic used.Our task was made considerably difficvult by the fact that the program had no comments in it.We searched the net for the program's logic finally we were able to understand the code.
	But there were a few flaws in the code:
1.The code didnt execute correctly when '-' or '^' symbol was entered.
2.There were no comments in the code.
3.There were no indentations in the code.
4.There was a small errror in the code when both '+' and '-' were included.
We indented the program suitably and disbanded for the day. 

Date : 24-10-10
Duration : 6:00pm - 8:30pm

	We assembled again at our team leader's room.We succeeded in doing the following tasks:
1.Read through the program carefully and added a few lines of code.Upon reexecution the program worked perfectly.The flaw lied in the preference orders where these 2 symbols werent mentioned.
2.We inserted suitable comments at all possible places.
3.By changing the preference orders of '+' and '-' we were able to overcome our 4th problem.

We are still faced with the following problems:
1.Only algebraic expressions can be evaluated.
2.We dont know how to pass a postfix expression to the computer for evaluation.

Our targets for the next phase are:
1.Try and include non algebraic expressions.
2.Try to find a way to pass the postfix expression to the computer.
3.Plot the graph.
