Patient fee Program () c++

I need help with understanding classes how they work and how interact.

Here is my code so, You can easily understand what is problem. I don't know how to make changes after I create an object with certain class.
Please help, I will really appreciate, Not waiting for solution just show the direction to dig.

Description of Programm:

16. Patient Fees

Here are some suggestions:

• The names, parameters, and return types of each function and class member function should be decided in advance.
• The program will be best implemented as a multifile program. Write a program that computes a patient’s bill for a hospital stay. The different components of the program are
• The PatientAccount class will keep a total of the patient’s charges. It will also keep track of the number of days spent in the hospital. The group must decide on the hospital’s daily rate.
• The Surgery class will have stored within it the charges for at least five types of surgery. It can update the charges variable of the PatientAccount class.
• The Pharmacy class will have stored within it the price of at least five types of medication. It can update the charges variable of the PatientAccount class.
• The main program.

The main program will design a menu that allows the user to enter a type of surgery, enter one or more types of medication, and check the patient out of the hospital. When the patient checks out, the total charges should be displayed.

#include <iostream>
#include<string>
#include<iomanip>
#include "classes.h"
using namespace std;

class PatientAccount {
private:
float patientCharge;
public:
PatientAccount(float charge=0){
    charge =patientCharge;
}

float getPatientCharge() {
    return patientCharge;
};
void setPatientCharge(float charge) {
    charge = patientCharge;
}


};


class Pharmacy {
private:
double medCharges;
public:
double getmedCharges(){
    return medCharges;
}
void setmedCharges(double charges) {
    charges=medCharges;
}
Pharmacy() {
double antibiotics = 10.00,
    antInausea =20.00,
    antiInflamatory =30.00,
    lightPain = 40.00,
    strongPain = 50.00;
    int choice;

    cout << "Here is the list of medications choose one you used! "<< endl;
    cout<< "To exit press 0 \n" <<endl;
    do {
      cout<<"(1) Antibiotics \n"
            "(2) Ant-Inausea \n"
            "(3) Anti-Inflamatory \n"
            "(4) Light Pain pills \n"
            "(5) Strong Pain pills \n"
            "(0) To EXIT" << endl;

        cin>>choice;

        switch (choice) {
            case 1: {
                double temp=getmedCharges()+antibiotics;
                setmedCharges(temp);
                break;}
            case 2: {
                double temp=getmedCharges()+antInausea;
                setmedCharges(temp);
                break;}
            case 3:{
                double temp=getmedCharges()+antiInflamatory;
                setmedCharges(temp);
                break;}
            case 4:{
                double temp=getmedCharges()+lightPain;
                setmedCharges(temp);
                break;}
            case 5:{
                double temp=getmedCharges()+strongPain;
                setmedCharges(temp);
                break;}
            case 6:
                choice = 0;
        };

    }
    while(choice!=0);

}

};



int main() {

Pharmacy spends;
PatientAccount someone;
cout<< someone.getPatientCharge()<<" $"<<endl;


return 0;
}