The second class should contain the code to perform the conversions. The pseudocode for prefix to postfix, which requires two stacks, is shown below: tokenize the string containing the prefix expression while there are more tokens push the token onto a reversal stack if it is not a space while the reversal stack is not empty pop the next token from the reversal stack if it is an operand push it onto the operand stack else it is an operator pop two operands off of the operand stack create a string with the two operands followed the operator push that string onto the operand stack pop the postfix expression off the stack The pseudocode for the postfix to prefix conversion, which requires only one stack, is shown below: tokenize the string containing the postfix expression while there are more tokens get the next token if it is a space skip it else if it is an operand push it onto the operand stack else it is an operator pop two operands off of the operand stack create a string with the operator followed by two operands push that string onto the operand stack pop the prefix expression off the stack