1. Infix to postfix conversion Process the tokens from a vector infixVect of tokens (strings) of an infix expression one by one When the token is an operand  Add it to the end of the vector postfixVect of token (strings) that is used to store the corresponding postfix expression When the token is a left or right parenthesis or an operator  If the token x is “(“ Push the token x onto the stack  if the token x is “)” Repeatedly pop a token y from the stack and push_back that token y to postfixVect until “(“ is encountered in the end of the stack. Pop “(“ from the stack. If the stack is already empty before finding a “(“, this expression is not a valid infix expression.  if the token x is a regular operator Step 1: Check the token y currently on the top of the stack. Step 2: If (i) the stack is not empty, (ii) y is not “(“ and (iii) y is an operator of higher or equal precedence than that of x,  then: pop the token y from the stack and push_back the token y to postfixVect, and repeat Step 1 again  else: push the token x onto the stack. When all tokens in infixVect are processed as described above, repeatedly pop a token y from the stack and push_back that token y to postfixVect until the stack is empty.

2. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) Infix to postfix conversion

3. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( stack Infix to postfix conversion

4. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( 1 Infix to postfix conversion stack

5. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( 1 + Infix to postfix conversion stack

6. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( 1 2 + Infix to postfix conversion stack

7. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( 1 2 + - Infix to postfix conversion stack

8. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) ( 1 2 + 3 - Infix to postfix conversion stack

9. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 - Infix to postfix conversion stack

10. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 - * Infix to postfix conversion stack

11. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 - 4 * Infix to postfix conversion stack

12. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 – 4 * - Infix to postfix conversion stack

13. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 – 4 * - ( Infix to postfix conversion stack

14. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 – 4 * 5 - ( Infix to postfix conversion stack

15. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) 1 2 + 3 – 4 * 5 - ( + Infix to postfix conversion stack

16. infixVect postfixVect ( 1 + 2 – 3 ) * 4 – ( 5 + 6) 1 2 + 3 – 4 * 5 6 - ( + Infix to postfix conversion stack

17. ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) infixVect postfixVect 1 2 + 3 – 4 * 5 6 + - Infix to postfix conversion stack

18. ( 1 + 2 – 3 ) * 4 – ( 5 + 6 ) infixVect postfixVect 1 2 + 3 – 4 * 5 6 + – Infix to postfix conversion stack