MathInterpreter

Mathematical expression interpreter for real-valued input. Works only with real numbers and returns real numbers. Uses the Shunting Yard Algorithm.

How to use:

A. Without variables

1. Have the mathematical expression you want to solve stored in a string in infix notation

   e.g. std::string expr = "-12.4 + exp(sin(rad(68))) * log10(96)";

2. Create a MathInterpreter object and call init_with_expr() initialize the interpreter with the given input expression.

   e.g.

   MathInterpreter inter; 
   inter.init_with_expr(expr);
   

3. Call calculate() to calculate the expression and save it in a double.

   e.g. double result = inter.calculate();

B. With variables

1. Have the mathematical expression you want to solve stored in a string in infix notation. Use dollar sign($) before and after variable names to mark variables.

   e.g. std::string expr = "-12.4 + exp(sin(rad($x$))) * log10($y$)"; //x and y are variables.

2. Create a MathInterpreter object and call init_with_expr() initialize the interpreter with the given input expression.

   e.g.

   MathInterpreter inter; 
   inter.init_with_expr(expr);
   

3. Use set_value() to set values for each registered variable.

   e.g.

   inter.set_value("x", 12.75);
   inter.set_value("y", 3.12);
   

4. Call calculate() to calculate the expression and save it in a double.

   e.g. double result = inter.calculate();

Notes:

• Function names can be all lowercase or all uppercase.
• Pi is recognized automatically when entered as a variable. e.g. sin(2*$pi$*5) or sin(2*$PI$*5)

Limitations:

• Supported operators: +, -, *, /, %, ^
• Supported functions: Given under enum FUNCTION
• Only real numbers are supported
• Results are returned only as double