stacks and queues how humans translate infix to postfix to translate infix to postfix notationyou follow similar set of rules to those for evaluating infix howeverthere are few small changes you don' do any arithmetic the idea is not to evaluate the infix expressionbut to rearrange the operators and operands into different formatpostfix notation the resulting postfix expression will be evaluated later as beforeyou read the infix from left to rightlooking at each character in turn as you go alongyou copy these operands and operators to the postfix output string the trick is knowing when to copy what if the character in the infix string is an operandyou copy it immediately to the postfix string that isif you see an in the infixyou write an to the postfix there' never any delayyou copy the operands as you get to themno matter how long you must wait to copy their associated operators knowing when to copy an operator is more complicatedbut it' the same as the rule for evaluating infix expressions whenever you could have used the operator to evaluate part of the infix expression (if you were evaluating instead of translating to postfix)you instead copy it to the postfix string table shows how + - is translated into postfix notation table translating + - into postfix character read from infix expression infix expression parsed so far postfix expression written so far aa+ +ba ab abc end + - + - ab+ ab+ccomments when you see the -you can copy the to the postfix string when you reach the end of the expressionyou can copy the notice the similarity of this table to table which showed the evaluation of the infix expression + - at each point where you would have done an evaluation in the earlier tableyou instead simply write an operator to the postfix output table shows the translation of + * to postfix this evaluation is similar to table which covered the evaluation of + *