Why is this program not running $??$

int main$()\{$

int choice;

do $\{$

$//$ Display menu options

cout $$ "Enter $1$ to Determine Miles$-$per$-$Gallon" $$ endl;

cout $$ "Enter $2$ to Determine Distance" $$ endl;

cout $$ "Enter $3$ to Determine Miles$-$per$-$Hour" $$ endl;

cout $$ "Enter $4$ to Exit" $$ endl;

cout $$ "Enter your choice: $"$;

$//$ Get user choice

cin $>>$ choice;

switch $($choice$)\{$

case $1$: $\{$

double mile, gallon;

Mileage car;

$//$ Prompt user for input

cout $$ "Enter Number of Miles: $"$;

cin $>>$ mile;

cout $$ "Enter Number of Gallons: $"$;

cin $>>$ gallon;

$//$ Set values in Mileage object

car.setMiles$($mile$)$;

car.setGallons$($gallon$)$;

$//$ Display calculated MPG

cout $$ "Miles per Gallon: $"$ fixed $$ setprecision$(2)$ car.getMPG$()$ endl;

break;

$\}$

case $2$: $\{$

double speed, time;

Distance dist;

$//$ Prompt user for input

cout $$ "Enter Speed $($miles$/$hour$)$: $"$;

cin $>>$ speed;

cout $$ "Enter Time $($hours$)$: $"$;

cin $>>$ time;

$//$ Set values in Distance object

dist.setSpeed$($speed$)$;

dist.setTime$($time$)$;

$//$ Display calculated distance

cout $$ "Distance Traveled: $"$ fixed $$ setprecision$(2)$ dist.getDistance miles" $$ endl;

break;

$\}$

case $3$: $\{$

double distance, time;

Speed spd;

$//$ Prompt user for input

cout $$ "Enter Distance $($miles$)$: $"$;

cin $>>$ distance;

cout $$ "Enter Time $($hours$)$: $"$;

cin $>>$ time;

$//$ Set values in Speed object

spd$.$setDistance$($distance$)$;

spd$.$setTime$($time$)$;

$//$ Display calculated speed

cout $$ "Speed: $"$ fixed $$ setprecision$(2)$ spd$.$getMPH miles per hour" $$ endl;

break;

$\}$

case $4$: $\{$

$//$ Exit the program

cout $$ "Exiting program. Goodbye!" $$ endl;

break;

$\}$

default:

$//$ Display error message for invalid input

cout $$ "Invalid choice. Please enter a number between $1$ and $4."$ endl;

$\}$

$\}$ while $($choice $!=4)$; $//$ Repeat until user chooses to exit

return $0$;

$\}$

$//$Mileage$.$h

#include

#include

using namespace std;

#pragma once

class Mileage

$\{$

private:

double miles; $//$ Distance traveled

double gallons; $//$ Gallons of gas used

public:

$//$ Set the value of miles

void setMiles$($double mile$)\{$

miles $=$ mile;

$\}$

$//$ Set the value of gallons

void setGallons$($double gallon$)\{$

gallons $=$ gallon;

$\}$

$//$ Get the value of miles

double getMiles$()\{$

return miles;

$\}$

$//$ Get the value of gallons

double getGallons$()\{$

return gallons;

$\}$

$//$ Calculate and return the miles per gallon

double getMPG$()\{$

return miles $/$ gallons;

$\}$

$\}$;

$//$Distance$.$h

#pragma once

class Distance

$\{$

private:

double speed; $//$ Speed in miles per hour

double time; $//$ Time taken in hours

public:

$//$ Set the value of speed

void setSpeed$($double s$)\{$

speed $=$ s;

$\}$

$//$ Set the value of time

void setTime$($double t$)\{$

time $=$ t;

$\}$

$//$ Get the value of speed

double getSpeed$()\{$

return speed;

$\}$

$//$ Get the value of time

double getTime$()\{$

return time;

$\}$

$//$ Calculate and return the total distance traveled

double getDistance$()\{$

return speed $*$ time;

$\}$

$\}$;

$//$Speed$.$h

#pragma once

class Speed

$\{$

private:

double distance; $//$ Distance traveled in miles

double time; $//$ Time taken in hours

public:

$//$ Set the value of distance

void setDistance$($double d$)\{$

distance $=$ d;

$\}$

$//$ Set the value of time

void setTime$($double t$)\{$

time $=$ t;

$\}$

$//$ Get the value of distance

double getDistance$()\{$

return distance;

$\}$

$//$ Get the value of time

double getTime$()\{$

return time;

$\}$

$//$ Calculate and return the speed in miles per hour

double getMPH$()\{$

return distance $/$ time;

$\}$

$\}$;