JAVA
Write a program that uses the class Calculator in Listing 9.12to create a more powerful calculator. This calculator will allowyou to save one result in memory and call the result back. Thecommands the calculator takes are
e for end
c for clear; sets result to zero
m for save in memory; sets memory equal to result
r for recall memory; displays the value of memory but does notchange result
You should define a derived class of the class Calculator thathas one more instance variable for the memory, a new main methodthat runs the improved calculator, a redefinition of the methodhandleUnknownOpException, and anything else new or
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