The Super$-$Duper Amazing Operating System $2\mathrm{.}0$ has a logging facility that applications can use to log messages to the Operating System's log files. The programming interface is$...$ odd.

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Logging the message requires the application programming to build a structure that has two fields: $$an integer enumeration that indicates the severity of a event. $$This enum defines four values: SEVERE, ERROR, WARNING, INFO. $$ The second field in the structure is a C$-$String that has the text of the error message. $$One logs a message to the log file by creating one of these structures, filling the appropriate values, and then passing a pointer to the structure to the SDAOS logging function. $$ The source code at the end of this question shows the C$++$ interface for this API.

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Using the Singleton and Facade patterns, $$write a class in C$++$ that an application can use as a central point to log errors in the operating system. $$ You class needs to be designed in a manner that an app client need only call one function for each of the four log message types, passing a C$++$ string object to the function.

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HINTS:

This problem requires you to apply the Facade pattern twice. $$Once for the API and then again on how to test this code if you aren't running on the Super$-$Duper Amazing Operating System.

Think carefully about the interface between the C$++$ String classes and the C$-$String data type.

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enum class ErrorLevel $\{$SEVERE$,$ ERROR, WARNING, INFO$\}$;

struct ErrorContext $\{$

ErrorLevel errlevel;

const char $*$ logmsg;

$\}$ logcontext;

extern void SDAOSlogger$($struct ErrorContext &logcontext$)$;