Calculator

Based on the parser, write a calculator that takes an expression of integer constants and evaluates the expression.

Example

% cat exp_file
5+4*(3-2)/1
% caculator exp_file
9

The extra amount of coding should be small.  Once you have the parser complete, you can make another copy of your code and instead of parsing for <program>, you let the calculator parse for <expression>.  You need to augment only the functions of all related production rules of <expression>.  The new code needs to evaluate the expression in the left-associative order during parsing.  In the next assignment of expression generation, similar code will be needed to convert expressions into assembly-like code that preserves left-associativity.

Submit the Calculator with the Parser.  The Makefile should produce both executables.