zybook $1\mathrm{.}7$ C$++$

Step $2$: Inspect the LabPrinter class

Inspect the LabPrinter class implemented in the LabPrinter.h file. Member functions Print$2$Plus$2()$ and PrintSecret$()$ print strings using

std$.$:cout.

Step $3$: Implement 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$20$ 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 button. Verify that the program's output is$,$ once again:

$2+2=4$

Unknown function: PrintPlus$2$

Secret string: $abc$

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

Once CallFunctionNamed$()$ is properly implemented, submitting the code should receive $10$ out of $10$ points. The program's output is

exactly the same as the implementation from step $1.$ But step $3\text{'}$s implementation uses the LabPrinter object and step $1$ does not.

Step $5$: Understand the difference

The unit test uses a different implementation of LabPrinter than what's shown in LabPrinter.h$.$ Calls to each member function are

tracked, so the unit test determines whether or not CallFunctionNamed$()$ was actually implemented according to lab requirements.

Most labs in this book are similar. Program output matters, but how the output is achieved matters more. Functions to implement will

commonly require use of an object passed as an argument.

LabPrinter.H $($read only$)$

#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

main.ccp

#include

#include

#include "LabPrinter.h$"$

using namespace std;

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

$//$ TODO: Implement this function after completing step $1$

$\}$

int main$()\{$

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

cout endl;

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

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

$//$ TODO: 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 $0$;

$\}$