A + B * C

operator	operand	input	action	why
		A + B * C	start
	A	+ B * C	shift A
+	A	B * C	shift +	empty < +
+	A B	* C	shift B
+ *	A B	C	shift *	+ < *
+ *	A B C		shift C
+	A (* B C)		reduce
	(+ A (* B C))		reduce

A * B + C

operator	operand	input	action	why
		A * B + C	start
	A	* B + C	shift A
*	A	B + C	shift *	empty < *
*	A B	+ C	shift B
	(* A B)	+ C	reduce	* ≥ +
+	(* A B)	C	shift +	empty < +
+	(* A B) C		shift C
	(+ (* A B) C)		reduce

(A + B) * C

operator	operand	input	action	why
		( A + B ) * C	start
(		A + B ) * C	shift (
(	A	+ B ) * C	shift A
( +	A	B ) * C	shift +	( < +
( +	A B	) * C	shift B
	(+ A B)	* C	reduce, discard ( )	)
*	(+ A B)	C	shift *	empty < *
*	(+ A B) C		shift C
	(* (+ A B) C)		reduce