Infix and Postfix

Algorithm for the Whole Conversion

Use the following steps to convert an infix expression to postfix form:

1. Scan the infix expression from left to right.
2. If the scanned symbol is an operand, add it directly to the output.
3. If the scanned symbol is (, push it onto the stack.
4. If the scanned symbol is an operator:
   • If the stack is empty, or the top of the stack is (, or the scanned operator has higher precedence than the operator on the top of the stack, push the scanned operator onto the stack.
   • Otherwise, pop operators from the stack and add them to the output until you find an operator with lower precedence or a (. Then push the scanned operator onto the stack.
5. If the scanned symbol is ), pop operators from the stack and add them to the output until ( is found. Remove the ( as well.
6. Repeat steps 1 to 5 until the entire infix expression has been scanned.
7. Pop any remaining operators from the stack and add them to the output.