Converting from infix to postfix
Read in infix string, one item at a time
If the item is an operand add to the postfix string
If the item is an operator push it on the stack if
b) if the precedence of the item at the top of the stack is < the item being processed
if the precedence of the item at the top of the stack is > the item being processed pop it to the postfix string
When the infix string is empty Pop the elements of the stack onto the postfix string to get the result