4. Given the following Invoice struct: struct Invoice { int orderID; string custName; string prodName; int prodQuantity; double unitPrice; } Inv [10]; Write a complete C++ program to do the following tasks: i) ii) iii) iv) Input 10 invoices (use void function inputData). Calculate the total payment for each invoice (use array). Every total payment is calculated using prodQuantity * unitPrice. (use void function totalPayment). Find the invoice that makes the highest payment. (use value returning function findHighest). Display the invoice information including its total payment (use void function displayInfo).