Repeat Exercises 6 and 7 in Chapter 7, but use an instance of ArrayList instead of an array. We will no longer need to know the maximum number of sales, so the methods will change to reflect this.

Exercises 6 and 7 in Chapter 7

Define the following methods for the class Ledger, as described in the previous exercise:

• getAverageSale()—returns the average value of all the sales
• getCountAbove(v)—returns the number of sales that exceeded v in value

Previous exercise:

Create a class Ledger that will record the sales for a store. It will have the attributes 

• sale—an array of double values that are the amounts of all sales 
• salesMade—the number of sales so far 
• maxSales—the maximum number of sales that can be recorded and the following methods:

Ledger(max)—a constructor that sets the maximum number of sales to max

• addSale(d)—adds a sale whose value is d
• getNumberOfSales—returns the number of sales made
• getTotalSales—returns the total value of the sales