Question

Write the program with language C++ ( THE PROGRAM SHOULD CONTAIN DECISION MAKING , LOOPING AND A FUNCTION ) to design a menu for a shop . When the user makes a choice , ask for quantity, then display the total charge with sale taxes . If the user enters a choice that is unavailable ,display an error message and ask him to re-enter.

Answer 1

SOURCE CODE:

*Please follow the comments to better understand the code.

**Please look at the Screenshot below and use this code to copy-paste.

***The code in the below screenshot is neatly indented for better understanding.

#include <iostream>
using namespace std;

// function to display menu.
void menu()
{
    cout<<"\n1. Show items\n";
    cout<<"2. Buy an item\n";
    cout<<"3. checkout\n";
    cout<<"Please enter your choice: ";
}

// function to display all the items.
void show_items()
{
    // Let's say only 2 items are available
    cout<<"Available items in the shop are:\n";
    cout<<"\t1. Pen ( 5 Rupees each )\n";
    cout<<"\t2. Pencil ( 3 Rupees each )\n";
}

int main()
{
   // declare variables
   double total=0;
   // LOOP HERE
   while(1)
   {
        // print menu
        menu();
        // read the choice
        int ch;
        cin>>ch;
      
        // DECISION MAKING USING IF ELSE
        if(ch==1)
        {
            show_items();
        }
        else if(ch==2)
        {
            show_items();
            cout<<"\nPlease enter the item number: ";
            int item;
            cin>>item;
            if(item==1)
            {
                cout<<"Enter the Quantity of pens: ";
                int quantity;
                cin>>quantity;
                cout<<quantity<<" Pens Successfully added to your cart."<<endl;
                cout<<"The cost of "<<quantity<<" pens is: "<<quantity*5;
                // add it to total
                total += quantity*5;
            }
            else if(item==2)
            {
                cout<<"Enter the Quantity of Pencils: ";
                int quantity;
                cin>>quantity;
                cout<<quantity<<" Pencils Successfully added to your cart."<<endl;
                cout<<"The cost of "<<quantity<<" pencils is: "<<quantity*3;
                // add it to total
                total += quantity*5;
            }
            else
            {
                cout<<"Invalid Choice";
            }
              
        }
        else if(ch==3)
        {
            cout<<"\n\nThank You for shopping. Your total bill is:\n";
            cout<<"Total Price: "<<total<<endl;
            // add 10% tax
            cout<<"Sales Tax: "<<total*0.1<<endl;
            cout<<"FINAL BILL: "<<total + total*0.1 <<endl;
            break;
        }
        else
        {
             cout<<"Invalid Choice. Please Try again..!!";
        }
   }
   return 0;
}

========

OUTPUT