Algorithm to convert infix expression into postfix expression.

 Algorithm:-

                       Suppose Q is an arithmetic expression written in infix notation . this algorithm find equivalent postfix expression P. 

1. Push “(“onto Stack, and add “)” to the end of Q.
2. Scan Q from left to right and repeat Step 3 to 6 for each element of Q until the Stack is empty.
3. If an operand is encountered, add it to P.
4. If a left parenthesis is encountered, push it onto Stack.
5. If an operator is encountered ,then:
   1. Repeatedly pop from Stack and add to P each operator (on the top of Stack) which has the same precedence as or higher precedence than operator.
   2. Add operator to Stack.
      [End of If]
6. If a right parenthesis is encountered ,then:
   1. Repeatedly pop from Stack and add to P each operator (on the top of Stack) until a left parenthesis is encountered.
   2. Remove the left Parenthesis