C++You will create a class called PostfixEvaluator. This class will have one static method called evaluate. This method takes a String as aparameter and returns a double that is the evaluation of the posfix expression in the parameter.You will also create a class called InfixToPostfix which has a single static method called “convert”. This method takes a string as a parameterwhich is an infix expression. Character in this expression will be either a single character positive digit or an operator. This method thentranslates that expression to a postfix expression.You only need to worry about the +,
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