View
218
Download
0
Tags:
Embed Size (px)
Citation preview
For Each The concept: go through each
element in a series of elements. For example, each cell in a range.
Example of For-EachShow address of each cell in Range:
For Each cell In _Worksheets("Sheet1").Range("A1:A10") MsgBox cell.Address Next cell
Second Example of For Each
Message for each negative cellFor Each cell In _Worksheets("Sheet1").Range("A1:A10") If cell.Value < 0 Then MsgBox cell.Address & " is Negative" End If Next cell
Third ExampleFor Each cell In _Worksheets("Sheet1").Range("A1:A10") If cell.Value < 0 Then cell.Interior.Color = RGB(255, 0, 0) End If Next cell
For Statement The For - Next statement allows us
to repeat a block of statements a certain number of times
Using the For statement we can perform a task repeatedly.
Warning ! Never change the value of the
counter variable within a For loop. This will cause unexpected (usually
bad) results.
Example of a For Loop
For i = 1 to 10MsgBox(“Hello”)
Next I
This will present 10 message boxes with the word hello in them. An extremely annoying program.
Dim j as Integer, k as Integer, m as Integer
k = 5m = 0For j = 1 to k m = j + mNext j
k
jj
1
Second Example of a For Loop
In this example, m will have the sum of all the integers from 1 to k.
Third Example of a For Loop
Dim i as Integer, j as Integer, k as Integer, m as Integer
m = 2k = 10j = 0For i = j To k Step m MsgBox(Cstr(i) & “ is an even number”)Next i
A.A. 1010B.B. 99C.C. 11D.D. 1111E. E. None of the None of the
AboveAbove
Question:
How many message boxes will appear?
For i = 1 to 10 MsgBox(“Hello”)Next i
Nested For Loops As with If statements, For loops can
be nested. The innermost loop will be executed
outer loop * inner loop times Interactions between the iteration
variables can create many effects.
Example of Nested For Loops Multiplication TableFor I = 1 to 10 For J = 1 to 10 msg = msg & Str(I*J) & “ “ Next J msg = msg & Chr(13)Next I
mj
k
1i
i
1
5
ijji
1
10
1
10
Mathematical Notation Remember that computer
languages were first invented to simplify mathematical calculations.
The For loop is similar to the mathematical terms pi and sigma.
How many message boxes will appear?k = 100For j = 1 To 100
For i = 1 To kMsgBox(“Hello”)
Next iNext j
A.A. 100100B.B. 10001000C.C. 11D.D. 10,00010,000E.E. None of the None of the
aboveabove
Question:
While Loop Sometimes we don’t know exactly
how many times we’ll be executing a block of code.
Sometimes we just want to continue executing it until we meet a condition.
Syntax of the While Loop
While conditionstatements to execute while condition is true
Wend As long as the condition is true the
statements inside this expression will continue to be executed.
Second Example of a While Loop
Asking the user for a number greater than 10
X = 0While (X < 10) X = Val(InputBox(“Number?”)Wend
Another Example
i = 1
While (i < 100 And _ Worksheets("Sheet1").Cells(i, 1).Value <> "") i = i + 1 Wend MsgBox i
What will the variable c equal when this loop is finished?
a = 0c = 10While(a < 10)
a = 2 * cc = c + 1
Wend
A.A. 1010B. B. 99C.C. 2020D.D. 1111E.E. 2121
Question:
Conclusion We have two basic iteration
(looping) statements For and While Using them we can perform
repetitive operations We can accumulate values