The equation file is a special text file that has a .242 extension. The equations in this file are in infix and/or postfix format. A typical equation file looks like the following: The equations file has to start with the tag <242> and ends with the tag . Within the start and end tags there are 1 or more sections. Section starts with

tag and ends with

tag. Within a section there are an optional infix and/or postfix sections. Infix starts with tag and ends with tag. Postfix starts with tag and ends with tag. Inside the infix/postfix sections you find 1 or more equations. Equation starts with tag and ends with tag. 1

At start, the user has to click the Load button. The load button will open a file chooser to select an equation file. The selected file will be displayed in the label next to the load button (e.g. c:\data\DS- Proj2.242) and then the file contents will be loaded as shown in previous figure if the file is valid(e.g. tags are balanced) . Valid file: you need to check and indicate whether the file tags are balanced or not. Meaning that each start tag has an end tag and they are closed in order. Note: This can be done using a stack similar to the balanced delimiters in equations. In the Equation Section you need to load equations from the 1st section from the file. For Infix equations: do convert the infix to postfix and then evaluate it. For postfix equations: do convert the postfix to prefix and then evaluate it. As shown in the previous figure. Note: we didnt cover prefix in lectures. You need to study it by yourself. At last, the Prev and Next buttons will navigate through equation section. If you click the Next button, it will display the equations from the 2nd section in the file if exists and so on. If you click the Prev button, it will display the equations from the previous section in the file if exists. To make the project more interesting: Weneedyoutoimplementthelinkedstackusinga cursor array. Youhavetodefine1coursearrayandwithinthiscursor array you can create as many stacks as needed. Yahoooo!