Download Numbers and Arithmetic Operations

CS4 –lecture 6
Wednesday, Jan 19, 2011
Roxana Gheorghiu
Numbers and Arithmetic
Operations
 Standard Arithmetic Operations:




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Addition (+)
Subtraction (-)
Division (/)
Multiplication (*)
Exponentiation (^)
 Level of precedence for arithmetic operations:
Numbers and Arithmetic
Operations
 Standard Arithmetic Operations -Level of
precedence for arithmetic operations:
 Addition (+)
 Subtraction (-)
 Division (/)
 Multiplication (*)
 Exponentiation (^)
Numbers and Arithmetic
Operations
 Level of precedence for arithmetic operations:
 Addition (+)
 Subtraction (-)
-LEVEL 3
 Division (/)
 Multiplication (*)
-LEVEL 2
 Exponentiation (^)
–LEVEL 1
 NOTE:
 1/0 = Infinity
 Math.Sqrt(-4) =NaN
(Not a Number)
Built-In Functions
 Modulo : x Mod y =the reminder when m is divided
my n
 Ex: 20 Mod 2 =0

15 Mod 4 =3
 Square root: Math.Sqrt( #number)
 Ex: Math.Sqrt(9) =3
Built-In Functions (cont.)
 The greatest integer less than or equal to a number:
Int(#number)
 Ex: Int(2.7) =2

Int(-2.7) =-3
 Rounding a number to r decimal places:
Math.Round(#number, #r) or Math.Round(#number)
 Math.Round(2.14 , 1) =2.1
 Math.Round(2.67) =3
Assignment Statement
Var = expression
 (1)
Dim myNumber as Double
myNumber =5.21
 (2)
Dim myNumber as Double =5.21
NOTE: Dim x as Integer =3, y as Double =5.3
String Properties and Methods
Dim str as String =“ My own String ”
 Length() =returns the number of characters in the string
 str.Length ->19
 ToUpper() =returns the string with letters capitalized
 str.ToUpper() ->” MY OWN STRING “
 ToLower() =returns the string with all letters in lowercase
format
 Str.ToLower() -> “ my own string “
 Trim() =returns the string with all spaces removed from
the front and back of the string
 str.Trim() -> “My own String”
String Properties and Methods
Dim str as String =“ My own String ”
Dim str2 as String = “own”
 Substring (m,n) =the substring that starts at
position m and its n characters long
 IndexOf(newString)
 str.IndexOf(str2) =str.IndexOf(“own”)
 str.Substring(0,5)
returns: “ My”
 Clear()
=creates an empty string
 str.Clear()
 str.Txt=“”
returns: 6
String Properties and Methods
 CStr(number) or number.ToString
 converts a number into a string
 CInt(string)
 converts a String into an Integer value
 CDbl(string)
 converts a String into a Double value
 &
 used to concatenate two strings
 str =“One” ; str1 =“ and two”
 str & str1 returns: “One and two”
 _
 the continuation character
Input Data from a Text Box
stringVar =textBox.Text
Ex: Dim str as String
str =txtName.Text
 If the input data will be used in a MATH expression
you will need first to convert it to Double or Integer
and then use it
Input Data from Dialog Box
stringVar = InputBox(prompt, title)
Ex: Dim name as String
Dim prompt, title as String
prompt =“Please give a name”
title =“Input box for a name”
name =InputBox(prompt, title)
Output Data Using a Message Box
MsgBox(prompt, button, title)
Ex: MsgBox (“Congratulation !”, 0, “Result Window”)
OR
MsgBox (“Congratulation !”) -> in this case the
title is the same string as the name of the main
window
Note: check *Dailly Schedule* on
www.cs.pitt.edu/~roxana/cs4/ for a complete list of
possible values for variable button
Application
(1) Write a VB program that asks a name as input
and it will copy that name in a list.
(2) Write a VB program that asks a name as input
and it will copy the first name in one list and the
last name in another list
(3) Continue exercise (2) by adding a new button
Del, that will delete an entry selected from any
list.