Learn to Program with Small Basic

Rounding to the Nearest Hundredth
Let’s explore Listing 7-2 a bit more. Using Round() or Floor() on the answer
gives you a whole number (dollars only). But what if you want to show the
amount of money to the nearest penny? How can you make Small Basic
round the answer to the nearest hundredth? Consider this statement:
Math.Floor(100 * x + 0.5) / 100
For example, if x = 2.8735, then 100 * x + 0.5 = 287.85, and the Floor()
method returns 287. Dividing 287 by 100 is 2.87, which is the result we want.
You can also round to the nearest hundredth using this statement:
Math.Round(x * 100) / 100
Let’s use this second technique to round the answer from Listing 7-2 to
the nearest penny. Add the following statement after line 11 in Listing 7-2:
A = Math.Round(A * 100) / 100
After computing A in line 11, the program rounds it to the nearest hundredth
(nearest penny) and saves the rounded answer back in A. If you run
the program now using the original inputs, the output will be $3207.14.
Perfect! Now we’re talking money!
TRY IT OUT 7-2
Helen is having a tough time at her store. She uses a calculator to add the 6% sales
tax to the purchase price. For example, if a customer’s total comes to $27.46, she
multiplies 27.46 by 1.06 to get 29.1076. But should she charge the customer $29.10
or $29.11? She doesn’t have time to do these calculations herself! Her store keeps
her much too busy!
Helen heard about your programming skills, so she’s coming to you for help.
She needs a program that lets her enter the total purchase amount. Then she wants
the program to add the sales tax, round the result to the nearest penny, and display
the answer. Create this program for Helen.
Abs(), Min(), and Max() Methods
The Math object provides methods for you to find the absolute value of a
number. When you calculate the absolute value of a number, you’re finding
its distance from zero, which will always be a positive number. For example,
the absolute value of both –1 and 1 is 1.
88 Chapter 7