This is the final project in my 2013-2014 semester in SJTU.

This is a simple GUI calculator written in C++. Use the other resources about GUI.

Simple calculator Revision history: Revised by dali zhang Novermber 2013 Originally written by Bjarne Stroustrup (bs@cs.tamu.edu) Spring 2004. This program implements a basic expression calculator. Input from cin; output to cout. The grammar for input is: Statement: Expression Print Quit Print: ; Quit: q; Expression : Term Expression ‘+’ Term e.g., 1+2, (1-2)+3, 23+1 Expression ‘-’ Term Term : Primary Term ‘’ Primary e.g., 1*2, (1-2)3.5 Term '/' Primary Term '%'Primary Primary : Number e.g., 1, 3.5 ‘(’ Expression ‘)’ e.g., (1+23) "-" Primary "+" Primary Primary ! Number : floating-point literal e.g., 3.14, 0.274e1

Input comes from cin through the Token_stream called ts.