Consider the partial implementation of the class BmiViewer, which allows the user to enter height in meters and weight in kilograms and returns the calculated BMI $($body mass index$)$:

BmiViewer declaration $($partial content of bmiviewer.h$)$

$$#ifndef BMIVIEWER$\_$H$$

#define BMIVIEWER$\_$H$$

#include $$

#include $$

#include $$

#include $$

#include $$

#include $$

#include

class BmiViewer : public QWidget $\{$

Q$\_$OBJECT

public:

$$ BmiViewer$()$;

$$ void calculateBmi$()$; private:

$$ QLineEdit$*$ heightEntry; QLineEdit$*$ weightEntry; QErrorMessage$*$ error;

$\}$;

#endif

$$

BmiViewer definition $($partial content of bmiviewer.cpp$)$

#include "bmiviewer.h$"$

BmiViewer::BmiViewer$()\{$

$$ setWindowTitle$("$BMI Calculator"$)$;$$

$$ QGridLayout$*$ layout $=$ new QGridLayout$($this$)$;

$$ QLabel$*$ inputWeightRequest $=$ new QLabel$("$Enter weight in kilograms $")$;

$$ weightEntry $=$ new QLineEdit$()$;

$$QLabel$*$ inputHeightRequest $=$ new QLabel$("$Enter height in meters $")$;

$$ heightEntry $=$ new QLineEdit$()$;

$$ setDecMode$()$;$//$for setting the LCD number mode setSegmentStyle$($QLCDNumber::Flat$)$;$//$for setting LCD style

$$layout$->$addWidget$($inputWeightRequest$,0,0)$;

$$ layout$->$addWidget$($weightEntry$,0,1)$;

$$ layout$->$addWidget$($inputHeightRequest$,1,0)$;

$$ layout$->$addWidget$($heightEntry$,1,1)$;

$$ setLayout$($layout$)$;

$\}$

void BmiViewer::calculateBmi$()\{\}$

content of main.cpp$$

#include $$

#include "bmiviewer.h$"$

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

$$QApplication app$($argc$,$ argv$)$; BmiViewer b;

$$b$.$show$()$;

$$return app.exec$()$;;$\}$

$$Complete the implementation of the class BmiViewer $($both header and cpp files$)$ so that

$$ it produces the following output:

$$ when the user enters the weight and height in the above Graphical User Interface $($GUI$)$ and clicks the Calculate button, it calculates the BMI as weight$/($height$$height$)$ and displays the result in the LCD number widget.

$$ if the user enters a non$-$number in either of the QLineEdits, it displays an error message as shown below:

Note: You only need to write down the lines of code that are required to complete the implementation. Indicate where the additional code must be added $($in both header and cpp files$).$ However, for the function calculateBmi$()$you must write down the complete implementation.$(12)$