Expression Evaluator Calculator Using Shunting Yard Algorithm

• There are 6 operator types (DIV,MUL,SUB,UNARY_SUB,ADD,PERCENT)

struct token {
   enum type t;
   union {
       int precedence;
       double operand;
   } fields;
};
#define PLUS 10 /* + */
#define SUB 10  /* - */
#define MUL 11 /* * */
#define DIV 11 /* / */
#define PER 11 /* p */
#define UNARY  12 /* unary - */

• Operands are only double values, highest precedence operator is UNARY(unary_sub)
• Numbers collected as double value in C
• A p B is doing A * (B/100)
• Program has a one Text Box and Button, computed result printed in MessageBoxA function
• Does not support open '(' and closed ')' parentheses

Requires MSVC C Desktop Development Toolset