Redundant function and help (New in C ++)

Assignment for C ++ introductory class, I understand programming concepts completely, but am struggling with the actual code creation part,
the task is to create a menu, apparently that is a popular task for new programmers, I got the first part but got confused trying to figure out the next 2 parts that request to print the order summary including products, quantities and the total price, and also calculate and print the total price of the order
any last minute help would be awesome so thanks to any answer my code is below with //
tickets where i got lost, i am also not sure if i have made a redundant code to show the price too

// Customer Names  & Product Menu
#include 
using namespace std;

//Function Prototypes
int getProduct (string)   
int getQuanity(string)
double printTotal(int,int)


int main(void)
{
    char selection = ' ';
    string name = "";



    //Customer Name input
    cout << "What is your name please? ==> "<< endl;
    getline(cin, name);

    //User enterned name displayed
    cout << "Welcome to Product Selection " + name << endl;

    do
    {
        cout << "Please choose your product from the Selections below" << endl;
        // Product Menu 
        cout << "Product Menu";
        cout << "========" << endl;
        cout << "Milk - 2.50" << endl;
        cout << "Eggs - 2.00" << endl;
        cout << "Soap - 3.50" << endl;
        cout << "X - Exit " << endl << endl;
        cout << "Enter selected Product: ";
        // Show the user selected product
        cin >> selection;

        switch (selection)
        {
        case '1':
            cout << "You have Selected Milk which is $2.50 " << endl;
            // getProduct  ? isnt this redundent as the menu is asking them to select a prodcut already?
            getQuanity;
            printTotal;
            break;
        case '2':
            cout << "You have Selected Eggs which are 2.00" << endl;
            getQuanity;
            printTotal;
            break;
        case '3':
            cout << "You have Selected Soap which is 3.50" << endl;
            getQuanity;
            printTotal;
            break;
        case 'X':
        case 'x':
            cout << "Thank you for your business" << endl;
            break;
            // invalid selection menu if option chosen outside menu selection
        default: cout << "Selection Unavaliable, Review selection & try again " << endl;

            // no break in the default case
        }
        cout << endl << endl;
    } while (selection != 'X' && selection != 'x');
// 

    return 0;
}



int getProduct(); // How do i get this function to Pull the string from the selection the user 
// made in the above menu? isnt the (switch
{
cout << "Your Selected Product is  "    



}






int getQuanity;
{

int getQuanity; 

cout << "Please Select The amount of this Item  you would like" << endl;
cin >> getQuanity;

return getQuanity;

}
double printTotal(int,int);
{
int printTotal  
cout <<"Your Total is"<< getQuanity * getProduct << "Thank you for your Business" << endl;

return printTotal;  
}