Data structures

Assume you have a string entered by the user that represents a valid expression for a mathematical equation that the user had entered. Write a c++ program to convert the input expression into a postfix expression using stack implementation. After that, you must evaluate the postfix expression using stack implementation to find the final answer. For example, if the user enters the following expression: Input: 942 Postfix Expression (First Output): 942 * - Result (Second Output): 1