Please answer both parts

Part C: Implement a simple stack-based post-fix calculator. Your program should accept integer operands and the +, - and * operators. Expressions should be entered one item per line with = on the final line to trigger the calculation and output of the result. Your program should detect invalid expressions (eg., too few operands, too many operands). Part D: Modify your stack implementation in such a way that a client application using your stack is unaware of the underlying array-based implementation. For instance, in a C or CH implementation, you would define function prototypes in h files and implementation details inc files. In Java and C#, you use interfaces. The application uses the interfaces (or h files) with no knowledge of how the functions are implemented. That way the array-based implementation could be replaced with a linked list-based one without any change to the client application. Part C: Implement a simple stack-based post-fix calculator. Your program should accept integer operands and the +, - and * operators. Expressions should be entered one item per line with = on the final line to trigger the calculation and output of the result. Your program should detect invalid expressions (eg., too few operands, too many operands). Part D: Modify your stack implementation in such a way that a client application using your stack is unaware of the underlying array-based implementation. For instance, in a C or CH implementation, you would define function prototypes in h files and implementation details inc files. In Java and C#, you use interfaces. The application uses the interfaces (or h files) with no knowledge of how the functions are implemented. That way the array-based implementation could be replaced with a linked list-based one without any change to the client application