Command-line calculator with variable assignments and trig functions
Uses shunting yard algorithm to convert expressions to reverse polish notation for order of operations
Accepts sin, cos, and log functions. Supports five operators: +, -, *, /,^.
Assigns mathematical constants: Pi = 3.14169 e = 2.718
Allows for variable assignment with keyword "let" (let = ) Exit by typing in "quit"
Compile g++ (Ubuntu 7.5.0-3ubuntu1~16.04) 7.5.0
g++ -std=c++11 calculator.cpp -o calculator