IN JAVA:

For this lab we will be building an expression translator to convert infix notation to postfix notation. Typical expressions to be evaluated are as follows:

infix expression	postfix expression
a + b - c	a b + c -
a - b + c * d	a b - c d * +
a + c - h / b * r	a c + h b / r * -
a + ( c - h ) / ( b * r )	a c h - b r * / +

An algorithm to accomplish the transformation is:

R1: Initially the operatorStack is empty

R2: For each operator of the infix string loop until the operator has been pushed onto the operatorStack:

If the operatorStack is empty or the operator has a higher precedence than the operator on the top of the operatorStack then push the operator onto the operatorStack

else pop the operatorStack and append that popped operator to the postfix string

R3: Once the end ot the input string is encountered

loop until the operatorStack is empty: Pop the operatorStack and append that popped operator to the postfix string

infix expression: a + b - h / b * r

infix	operatorStack	postfix
a	empty	a
+	+	a
c	+	a c
-	-	a c +
h	-	a c + h
/	-/	a c + h
b	-/	a c + h b
*	-*	a c + h b /
r	-*	a c + h b / r
	-	a c + h b / r *
	empty	a c + h b / r * -