Visual Basic.NET How to Program (PDF)

238 Procedures Chapter 6
b) Math method Exp is the exponential method that calculates e x .
c) A recursive procedure is one that calls itself.
d) Conversion from type Single to type Double requires a widening conversion.
e) Variable type Char cannot be converted to type Integer.
f) When a procedure recursively calls itself, it is known as the base case.
g) Forgetting to return a value from a recursive procedure when one is needed results in a
logic error.
h) Infinite recursion occurs when a procedure converges on the base case.
i) Visual Basic supports Optional arguments.
j) Any problem that can be solved recursively also can be solved iteratively.
6.3 For the program in Fig. 6.27, state the scope (either class scope or block scope) of each of the
following elements:
a) The variable i.
b) The variable base.
c) The method Cube.
d) The method FrmCubeTest_Load.
e) The variable output.
6.4 Write an application that tests whether the examples of the Math class method calls shown
in Fig. 6.7 actually produce the indicated results.
6.5 Give the procedure header for each of the following:
a) Procedure Hypotenuse, which takes two double-precision, floating-point arguments,
side1 and side2, and returns a double-precision, floating-point result.
b) Procedure Smallest, which takes three integers, x, y and z, and returns an integer.
c) Procedure Instructions, which does not take any arguments and does not return a
value.
d) Procedure IntegerToSingle, which takes an integer argument, number, and returns
a floating-point result.
6.6 Find the error in each of the following program segments and explain how the error can be
corrected:
1 ' Fig. 6.27: CubeTest.vb
2 ' Printing the cubes of 1-10.
3
4 Public Class FrmCubeTest
5 Inherits System.Windows.Forms.Form
6
7 Friend WithEvents lblOutput As Label
8
9 ' Visual Studio .NET generated code
10
11 Dim i As Integer
12
13 Private Sub FrmCubeTest_Load(ByVal sender As System.Object, _
14 ByVal e As System.EventArgs) Handles MyBase.Load
15
16 Dim output As String = ""
17
Fig. Fig. 6.27 6.27 Printing the results of cubing 10 numbers (part 1 of 2).