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Unit 8: Understanding Function and Procedure

8.7 Summary

• User defined function can consists of one or more variables.
• Comparing function procedures with sub-procedures are invoked with call statements.
• Top-down design and structured programming emerged as techniques to enhance
programming productivity.

8.8 Keywords

Function procedure: In addition to using built-in function, we can define function of our own.
These new function, called function procedure or user-defined function.

Future value function: The value of an asset or cash at a specified date in the future that is
equivalent in value to a specified sum today.
Parameters: The variables appearing in the top line are called parameters.

Region directive: The Region directive is used to make a program more readable or to create an
outline for a program.

Stepwise refinement: Repeatedly using a “divide-and-conquer” approach Repeatedly using a
“divide-and-conquer” approach.

1. Suppose a program contains the lines

Dim n As Double, x As String
lstOutput.Items.Add(Arc(n, x))

What types of inputs (numeric or string) and output does the function Arc
have?
2. Suppose a fixed amount of money is deposited at the beginning of each
month into a savings account paying 6% interest compounded monthly.
After each deposit is made, [new balance] = 1.005 * [previous balance one
month ago] + [fixed amount]. Write a program that requests the fixed
amount of the deposits as input and displays the balance after each of the
first four deposits. A sample outcome when 800 is typed into the text box
for the amount deposited each month follows.
Month 1 800.00

Month 2 1,604.00
Month 3 2,412.02
Month 4 3,224.08

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