Billing System Total has an output of 0

Question

I am a first-year college student and I am currently having trouble with this program I am working on, It is about a billing system. I managed to do everything but the final part, which is printing the total, tax, and the final bill. Anything I try to do either gives me a wrong answer or a 0. Please help.

#include <iostream>
#include <string.h>
#include <iomanip>
#define MAX 8

using namespace std;

struct menuItemType{
    string menuItem;
    double menuPrice;
};

menuItemType menulist[MAX];

void getData();
void showMenu();
int printCheck(void);
//int b[8] = {0,0,0,0,0,0,0,0};

int main(){
    cout << "Welcome to Mavel's Restaurant\n\n";
    cout << "------------ Menu ------------ \n";
    showMenu();
    getData();
    int choice;
    char add;
    
    do {
    cout << "Enter choice: ";
    cin >> choice;
    
        switch (choice){
            
            case 1:
                cout<< "You ordered Plain Egg.\n";
                break;
            case 2:
                cout<< "You ordered Bacon and Egg.\n";
                break;
                
            case 3:
                cout<< "You ordered a muffin.\n";
                break;
            
            case 4:
                cout<< "You ordered French Toast.\n";
                break;
            
            case 5:
                cout<< "You ordered Fruit Basket.\n";
                break;
            
            case 6:
                cout<< "You ordered Cereal.\n";
                break;
                
            case 7:
                cout<< "You ordered Coffee.\n";
                break;
                
            case 8:
                cout<< "You ordered Tea.\n";
                break;
                
            default:
                cout<< "Invalid Choice.";
                break;  
            
        }
        
    cout<< "Would you like to order another item? [Y]es / [N]o : ";
    cin >> add;
    
    if (add == 'N'||add =='n'){
     printCheck();
}

}
while (add == 'Y'|| add == 'y');

}


void getData(){
    
    menulist[0].menuItem = "Plain Egg";
    menulist[0].menuPrice = 140.50;
    
    menulist[1].menuItem = "Bacon and Egg";
    menulist[1].menuPrice = 245.00;
    
    menulist[2].menuItem = "Muffin";
    menulist[2].menuPrice= 295.00;
    
    menulist[3].menuItem = "French Toast";
    menulist[3].menuPrice = 495.00;
    
    menulist[4].menuItem = "Fruit Basket";
    menulist[4].menuPrice = 555.00;
    
    menulist[5].menuItem = "Cereal";
    menulist[5].menuPrice = 385.00;
    
    menulist[6].menuItem = "Coffee";
    menulist[6].menuPrice = 415.00;
    
    menulist[7].menuItem = "Tea";
    menulist[7].menuPrice = 333.00;
    
}

void showMenu(){
    cout << "[1] Plain Egg\t\tPhp140.50\n";
    cout << "[2] Bacon and Egg\tPhp245.00\n";
    cout << "[3] Muffin\t\tPhp295.00\n";
    cout << "[4] French Toast\tPhp495.00\n";
    cout << "[5] Fruit Basket\tPhp555.00\n";
    cout << "[6] Cereal\t\tPhp385.00\n";
    cout << "[7] Coffee\t\tPhp415.00\n";
    cout << "[8] Tea\t\t\tPhp333.00\n\n";
}

double total = 0;

int printCheck(){
    
    getData();
    double total = 0 , tax, totalbill;
    
    for (int i = 0; i < 8; i++){
        
    
        total += menulist[i].menuPrice;
        
    }   
    
    
    
    tax = total * 0.05; 
    totalbill = total+tax; 
    
        cout << "----------------------------------------------\n";
       cout << "Tax\t\t" << tax<< endl;
       cout << "Amount Due\tPhp" << totalbill << endl;
       cout << "----------------------------------------------\n";
    
    return total;
}

Answer 1

Your code is a bit all over the place, with some small reorganization you can get the intended result, here is a possible fix, with comments where needed:

Live sample

#include <iostream>
#include <string.h>
#include <iomanip>

#define MAX 8

using namespace std; // I would avoid using namespace std, explanation ahead

struct menuItemType
{
    string menuItem;
    double menuPrice;
};

//menuItemType menulist[MAX]; //does not need to be global

void getData(menuItemType *menulist);
void showMenu();
int printCheck(double total); // pass the total to the printCheck() function

int main()
{
    menuItemType menulist[MAX]; // go local when possible

    cout << "Welcome to Mavel's Restaurant\n\n";
    cout << "------------ Menu ------------ \n";

    showMenu(); // here you could also pass menulist and print the menu using the data
                //it would be easier to refactor if you add a menu item, try it

    getData(menulist);
  
    int choice;
    char add;
    double total = 0;

    do
    {
        cout << "Enter choice: ";
        cin >> choice;

        // do the math in the cycle so you can keep track of the sum of selected items

        if(choice > 0 && choice <= MAX)
            total += menulist[choice - 1].menuPrice;

        switch (choice) // if you want to separate logic from UI, this could 
                        // be a separate function, i.e. printChoice(choice);
        {

        case 1:
            cout << "You ordered Plain Egg.\n";
            break;
        case 2:
            cout << "You ordered Bacon and Egg.\n";
            break;

        case 3:
            cout << "You ordered a muffin.\n";
            break;

        case 4:
            cout << "You ordered French Toast.\n";
            break;

        case 5:
            cout << "You ordered Fruit Basket.\n";
            break;

        case 6:
            cout << "You ordered Cereal.\n";
            break;

        case 7:
            cout << "You ordered Coffee.\n";
            break;

        case 8:
            cout << "You ordered Tea.\n";
            break;

        default:
            cout << "Invalid Choice.";
            break;
        }

        cout << "Would you like to order another item? [Y]es / [N]o : ";
        cin >> add;

        if (add == 'N' || add == 'n') // this condition is also refactorable, you could  
                                      // simply move the print to after the loop ends
        {
            printCheck(total);
        }

    } while (add == 'Y' || add == 'y');

    //printCheck(total); //here
}

void getData(menuItemType *menulist)
{
    menulist[0].menuItem = "Plain Egg";
    menulist[0].menuPrice = 140.50;

    menulist[1].menuItem = "Bacon and Egg";
    menulist[1].menuPrice = 245.00;

    menulist[2].menuItem = "Muffin";
    menulist[2].menuPrice = 295.00;

    menulist[3].menuItem = "French Toast";
    menulist[3].menuPrice = 495.00;

    menulist[4].menuItem = "Fruit Basket";
    menulist[4].menuPrice = 555.00;

    menulist[5].menuItem = "Cereal";
    menulist[5].menuPrice = 385.00;

    menulist[6].menuItem = "Coffee";
    menulist[6].menuPrice = 415.00;

    menulist[7].menuItem = "Tea";
    menulist[7].menuPrice = 333.00;
}

void showMenu()
{
    cout << "[1] Plain Egg\t\tPhp140.50\n";
    cout << "[2] Bacon and Egg\tPhp245.00\n";
    cout << "[3] Muffin\t\tPhp295.00\n";
    cout << "[4] French Toast\tPhp495.00\n";
    cout << "[5] Fruit Basket\tPhp555.00\n";
    cout << "[6] Cereal\t\tPhp385.00\n";
    cout << "[7] Coffee\t\tPhp415.00\n";
    cout << "[8] Tea\t\t\tPhp333.00\n\n";
}

// now can simply print the check
int printCheck(double total)
{
    double tax = total * 0.05;
    double totalbill = total + tax;

    cout << "----------------------------------------------\n";
    cout << "Tax\t\t" << tax << endl;
    cout << "Amount Due\tPhp" << totalbill << endl;
    cout << "----------------------------------------------\n";

    return total; // you're not using this return value, you may aswell make the function return type void
}

For more information whether you should use using namespace std; check this link:

Why is "using namespace std;" considered bad practice?

Note that the code still have some weaknesses, namely the lack of input validation, if, as an example, your input is not a number when you are prompted to give a choice you have a problem. If you want to learn more about this there are many threads in SO you can find, for instance:

Good input validation loop using cin - C++