Billing systems

#include<iostream>
using namespace std;

double getUnitprice(int itemCode);

int main(){

  double invoice[10][4];
  int i=0; char more; char date[100];

  cout << "\n\n********* Here are the Item prices for your information********** \n\nItem code\tUnitPrice\n\n1\t100\n2\t200\n3\t300\nInvalidCode\t0\n\n";
  cout << "Enter the date: ";
  cin >> date;
  
  do {
 
    cout << "\n\nItem code: ";
    cin >> invoice[i][0];
    cout << "Quantity : ";
    cin >> invoice[i][1];
    
    invoice[i][2] = getUnitprice(invoice[i][0]); 
    invoice[i][3] = invoice[i][1] * invoice[i][2]; 
    
    cout << "Do you have any other items to be entered next (y/n) ? ";
    cin >> more;
  
    i++;
  } while(more == 'y');
    
 
  cout << "\n\n-----------------------------\n\n";
  cout << "Date : " << date << "\n\n";
  
  cout << "ItemCode|Quantity|UnitPrice|TotalPrice\n\n";
  int tot=0;
  for(int k=0; k<i; k++)   
    
	{
		for(int l=0; l<4; l++) 
		{
		    cout << invoice[k][l]  << "\t";		   
		}
		cout << endl;
		tot = tot + invoice[k][3];
	}

  cout << "\n\nTotal : " << tot;
  cout << "\n\n-----------------------------\n\n\n";
  
  return 0;
}

double getUnitprice(int itemCode){
  double price;
  switch (itemCode)
  {
    case 1: price = 100;
      break; 
    case 2: price = 200;
      break;
    case 3: price = 300;
      break;
    default: price = 0;
      break;
  }
  return price;
}