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Provide a method with signature public int calculation(String s) which will take a postfix expression as an input and return the calculation result of this expression. (Assume the expression only have +,-,*,/ and parentheses)

Provide a method with signature public String InToPostFix (String s) which will accept a infix expression as a string and convert it into a post fix expression and returned the postfix expression as a string (Assume the expression only have +,-,*,/ and parentheses) . ( Check the pusduo code on the slides.)