mathShell.3bsc

A novice implementation of a simple math Shell

MATH SHELL: By Hariharan and Abhiishek S Chugh
	-173209		-171201		
	-III B.Sc. Mathematics (Honours)




ABOUT:
The project is a Simple Math Shell project that enables the
User to perform the operations of addition, multiplication,
division and subtraction of both variables(declared by the user)
and of numerical values entered by the User.

The shell can also open perform the functions that a usual
shell can except 'alias'.

The shell first tokenizes the input string taken using the
readline library and adds it to the history of commands
entered. Then it goes to the 'function check' which
returns an integer which transfers the control to a switch
case which calls the functions. Before calling the function
the program fork a new process and executes all the new
functions in that new process.

FILES:
characterStack.c -> This file has all the functions that help to 
		    initialize, Push, Pop and return the Topvalue
		    of the character pointer stack.

doubleStack.c -> This file has all the functions that help to 
		 initialize, Push, Pop and return the Topvalue
		 of the stack of type double.

functionheader.h -> This file houses the definitions of all the 
		    functions used in the project.

functions.c -> This file contains functions that return values pertaining
		to the processes that the shell performs.

infixToSuffix.c -> This file contains the functions to convert the entered 
		   expression (in the form of tokens) into a Suffix expression.
		   Sample:
		   	<99><+><88><*><77></><66> --> <99><88><77><66></><*><+>

		   For eg.
		   	    ~/cherry_shell/:)/>>> 3+4
		   	    7.00
		    	    ~/cherry_shell/:)/>>> 3+4*6
			    27.00
			    ~/cherry_shell/:)/>>> 27.3+4.6*7/2
			    43.40
			    ~/cherry_shell/:)/>>> 

dynamicDeclare.c -> This file contains the functions that dynamically declare variables
		    in the shell. The input is again a tokenized input which stores all 
		    the declared variables in string format and then call the values of 
		    the variables by inputing "all variables" command on the shell.
		    Moreover, for the variables that are defined by the User, the User
		    can then opt to perform arithematic operations with those declared 
		    variables too.
		    For eg.
		            ~/cherry_shell/:)/>>> x=3
		    	    ~/cherry_shell/:)/>>> all variables
			    x=3
			    ~/cherry_shell/:)/>>> y=4
			    ~/cherry_shell/:)/>>> all variables
			    y=4
			    x=3
			    ~/cherry_shell/:)/>>> x+y
			    7
			    ~/cherry_shell/:)/>>> x=9
			    ~/cherry_shell/:)/>>> all variables
			    x=9
			    y=4
			    ~/cherry_shell/:)/>>> 



main.c -> This is the main file has the program written.

makefile -> This is the build used to compile the project