C$++$Please show full code and explanation. Step $1$: Producing correct output

Three commented$-$out lines of code exist in main $().$ Uncomment the lines and click the "Run program" button. Verify that the program's

output is:

$2+2=4$

Unknown function: PrintPlus$2$

secret string: "abc"

Submit your code for grading. Your submission will pass the "Compare output" test only, achieving $1$ of the possible $10$ points.

Step $2$: Inspecting the LabPrinter class

Inspect the LabPrinter class implemented in the LabPrinter.h file. Access LabPrinter.h by clicking on the orange arrow next to main.cpp at the top of the coding window. Member functions Print$2$Plus$2()$ and Printsecret $()$ print strings using std: : cout.

Step $3$: Implementing CallFunctionNamed$()$

Remove the three uncommented lines from main$().$ Then implement the CallFunctionNamed $()$ function in main.cpp to handle three

cases:

If functionName is "Print$2$Plus$2",$ call printer's Print$2$Plus$2()$ member function.

If functionName is "PrintSecret", call printer's Printsecret $()$ member function.

If functionName is anything other than the two strings mentioned above, print "Unknown function: xyz$",$ where xyz is

functionName's value.

After implementing CallFunctionNamed $(),$ click the "Run program" button. Verify that the program's output is$,$ once again:

$2+2=4$

Unknown function: PrintPlus$2$

secret string: "abc"

Step $4$: Submitting code for $\frac{10}{10}$ points

main.cpp

#include

#include

#include "LabPrinter.h$"$

using namespace std;

void CallFunctionNamed$($LabPrinter& printer, string functionName$)\{$

$//$ Only implement this function after completing step $1$

$\}$

int main $($int argc, char $*$argv$[])\{$

LabPrinter printer$("$abc$")$;

$//$ Step $1$:

$//$ Uncomment the block below and submit code for grading. Note that the

$//$ submission passes the "Compare output" test, but fails each unit test.

$/*$

cout endl;

cout $$ "Unknown function: PrintPlus$2"$ endl;

cout $$ "Secret string: $\backslash "$abc$\backslash ""$ endl;

$*/$

$//$ After completing step $1$:

$//$ Remove lines of code from step $1$ and implement the CallFunctionNamed

$//$ function above main$().$

CallFunctionNamed$($printer$,$ "Print$2$Plus$2")$;

CallFunctionNamed$($printer$,$ "PrintPlus$2")$;

CallFunctionNamed$($printer$,$ "PrintSecret"$)$;

return $0$;

$\}$

LabPrinter.h

#ifndef LABPRINTER$\_$H

#define LABPRINTER$\_$H

#include

#include

class LabPrinter $\{$

protected:

const std::string secret;

public:

LabPrinter$($std::string secretStringValue$)$ : secret$($secretStringValue$)\{$

$\}$

virtual void Print$2$Plus$2()\{$

using namespace std;

cout endl;

$\}$

virtual void PrintSecret$()\{$

using namespace std;

cout $$ "Secret string: $\backslash ""$ secret endl;

$\}$

$\}$;

#endif