Một số ví dụ ứng dụng visual basic 6 0

ðề 2 & 10:Lấy dữ liệu cổng com.Vẽ ñồ thịGiao diện Chương trình: Private Sub cmdrun_Click Timer1.Enabled = True End Sub Private Sub cmdStop_Click Timer1.Enabled = False End Sub Private Su

ðề 1 và 7:Tính lãi suất…

Giao diện:

Chương trình:

Private Sub cmdXacDinh_Click()

Dim SoTienCo As Single, LaiSuat As Single, SoTienCan As Single, SoNamCanGui As Single

SoTienCo = Text1

SoTienCan = Text2

LaiSuat = Text3

If SoTienCo >= SoTienCan Then

Text4 = "aaaa"

Else

Do

SoTienCo = SoTienCo * (1 + LaiSuat / 100)

SoNamCanGui = SoNamCanGui + 1

Loop While SoTienCo <= SoTienCan

Text4 = SoNamCanGui

Text5 = SoTienCo

End If

End Sub

ðề 2 & 10:Lấy dữ liệu cổng com.Vẽ ñồ thị

Giao diện

Chương trình:

Private Sub cmdrun_Click()

Timer1.Enabled = True

End Sub

Private Sub cmdStop_Click()

Timer1.Enabled = False

End Sub

Private Sub Form_Load()

MSComm1.PortOpen = True

End Sub

Private Sub Form_Unload(Cancel As Integer)

MSComm1.PortOpen = False

End Sub

Private Sub Timer1_Timer()

Static x(), t(), i

ReDim Preserve x(i) ' khai bao lai mang

ReDim Preserve t(i) ' khai bao lai thoi gian

If i = 0 Then Picture1.PSet (Picture1.Height, 0) ' khoi tao diem dau con tro

x(i) = MSComm1.Input ' doc gia tri vao tu cong com1

Picture1.Line -(Picture1.Height - x(i) * 100, t(i) * 100) ' ve do thi

End Sub

ðề3:Vẽ y=(ax2 +b)x.ðưa ra màn hình ñồ thị &ñiểm cực tiểu

Giao diện:Form1

Viết chương trình trong Form2:

Private Sub Form_GotFocus()

Dim x As Single, y As Double, GTCT As Double, GTCD As Double, y1 As Double

Dim i As Integer, a As Single, b As Single

'Form2.BackColor = vbWhite

a = Form1.Text1

b = Form1.Text2

've he truc toa do

Form2.Line (0, Form2.Height / 2)-(Form2.Width, Form2.Height / 2) Form2.Line (Form2.Width / 2, 0)-(Form2.Width / 2, Form2.Height) 'khac so

For i = -3 To 3

CurrentX = (i + 3) * Form2.Width / 6

CurrentY = Form2.Height / 2 + 6

Print i

Next

For i = -30 To 30 Step 2

CurrentX = Form2.Width / 2 - 6

CurrentY = (i + 30) * Form2.Height / 60

Print i

Next

' ve do thi trong khoang -3 den 3 doi voi gia tri cua x va -30 den 30 doi voi gia tri cau y

i = 0

For i = 0 To 500

x = -3 + i * 6 / 500

y = a * x ^ 3 + b * x

Form2.Line -((x + 3) * Form2.Width / 6, Form2.Height - (y + 30) * Form2.Height / 60)

Next

'tinh cuc tri

' y' = 3a*x^2 + b

If a * b > 0 Or a = 0 Then

Form1.Text3 = "k0 ton tai"

Form1.Text4 = "k0 ton tai"

Else

x = b / (3 * a)

GTCT = a * x ^ 3 + b * x

x = -b / (3 * a)

GTCD = a * x ^ 3 + b * x

If GTCT > GTCD Then

y1 = GTCT

GTCT = GTCD

GTCD = y1

End If

Form1.Text3 = GTCT

Form1.Text4 = GTCD

End If

ðề 4:Nhân ma trận

Giao diện:

Private Sub cmdcong_Click()

Dim i, j, mang1(4, 4) As Single, mang2(4, 4) As Single, mang3(4, 4) As Single

' nhap so lieu vao mang

For i = 0 To 3

For j = 0 To 3

mang1(i, j) = Text1(i * 4 + j)

mang2(i, j) = Text2(i * 4 + j)

Next

Next

' thuc hien phep cong

For i = 0 To 3

For j = 0 To 3

mang3(i, j) = mang1(i, j) + mang2(i, j)

Next

'dua ket qua ra man hinh

For i = 0 To 3

For j = 0 To 3

Text3(i * 4 + j) = mang3(i, j)

Next

Next

End Sub

Private Sub cmdnhan_Click()

Dim i, j, mang1(4, 4) As Single, mang2(4, 4) As Single, mang3(4, 4) As Single

Dim k

' nhap so lieu vao mang

For i = 0 To 3

For j = 0 To 3

mang1(i, j) = Text1(i * 4 + j)

mang2(i, j) = Text2(i * 4 + j)

Next

Next

' thuc hien phap nhan

For i = 0 To 3

For j = 0 To 3

For k = 0 To 3

mang3(i, j) = mang3(i, j) + mang1(i, k) * mang2(k, j)

Next

Next

Next

'dua ket qua ra man hinh

For i = 0 To 3

For j = 0 To 3

Text3(i * 4 + j) = mang3(i, j)

Next

Next

ðề 5:Nhập và phát xung RTS & DTR

Dim xung_rts As Integer, xung_dtr As Integer

Private Sub cmdphat_Click()

Timer1.Interval = Round(1000 / (2 * Text3)) ' dinh thoi gian timer1 tuong ung voi tan so

Timer1.Enabled = True ' cho phep timer1 hoat dong

xung_rts = Text1

xung_dtr = Text2

End Sub

Private Sub Form_Load()

MSComm1.PortOpen = True

End Sub

Private Sub Form_Unload(Cancel As Integer)

MSComm1.PortOpen = False

End Sub

Private Sub Timer1_Timer()

Static x As Boolean, y As Boolean

' phat xung ra chan RTS

If xung_rts > 0 Then

If x = False Then

MSComm1.RTSEnable = False ' RTS = 0

x = True

Else

MSComm1.RTSEnable = True ' RTS = 1

x = False

xung_rts = xung_rts - 1

Text4 = xung_rts

End If

End If

' phat xung ra chan DTR

If xung_dtr > 0 Then

If y = False Then

MSComm1.DTREnable = False ' DTR = 0

y = True

Else

MSComm1.DTREnable = True ' DTR = 1

y = False

xung_dtr = xung_dtr - 1

Text5 = xung_dtr

End If

End If

' dung timer1 khi da phat het xung

If (xung_rts = 0) And (xung_dtr = 0) Then Timer1.Enabled = False ' dung timer1

MsgBox "da phat xong" ' bao da phat xong End If

ðề 6:Viết chương trình ñèn giao thông

Private Sub cmdrun_Click()

Timer1.Enabled = True

End Sub

Private Sub cmdstop_Click()

Timer1.Enabled = False

' tat cac den

For j = 0 To 11

Label1(j).BackColor = vbBlack Next

End Sub

Private Sub Form_Load()

Dim i

For i = 0 To 11

Label1(i).BackColor = vbBlack

Next i

End Sub

Private Sub Timer1_Timer()

Dim x As Integer, v As Integer, d As Integer

Dim j

Static t

x = Text1

v = Text2

d = x + v

' thuat giai (tinh theo 1 chu ky thoi gian)

' x -v -d - duong 1

' d -x -v - duong 2

For j = 0 To 11

Label1(j).BackColor = vbBlack

Next

' chon cho duong 1

Select Case t

Case Is <= x: Label1(0).BackColor = vbGreen ' xanh

Label1(6).BackColor = vbGreen Case Is <= x + v: Label1(1).BackColor = vbYellow ' vang

Label1(7).BackColor = vbYellow Case Is <= 2 * (x + v): Label1(2).BackColor = vbRed ' do

Label1(8).BackColor = vbRed End Select

'chon cho duong 2

Select Case t

Case Is <= d: Label1(5).BackColor = vbRed ' do

Label1(11).BackColor = vbRed Case Is <= d + x: Label1(3).BackColor = vbGreen ' xanh

Label1(9).BackColor = vbGreen Case Is <= 2 * (x + v): Label1(4).BackColor = vbYellow ' vang

Label1(10).BackColor = vbYellow

t = t + 1

If t > 2 * d Then t = 0

'##### doan nay dung de tao ra "dong ho" => k0 can phai them vao

Label3 = Time

'##################################3

End Sub

ðề 8:Vẽ ñồ thị y=ax(bx+c)

Private Sub Form_GotFocus()

Dim x As Single, y As Double, GTCT As Double, GTCD As Double, y1 As Double

Dim i As Integer, a As Single, b As Single

'Form2.BackColor = vbWhite

a = Form1.Text1

b = Form1.Text2

've he truc toa do

Form2.Line (0, Form2.Height / 2)-(Form2.Width, Form2.Height / 2) Form2.Line (Form2.Width / 2, 0)-(Form2.Width / 2, Form2.Height) 'khac so

For i = -3 To 3

CurrentX = (i + 3) * Form2.Width / 6

CurrentY = Form2.Height / 2 + 6

Print i

Next

For i = -30 To 30 Step 2

CurrentX = Form2.Width / 2 - 6

CurrentY = (i + 30) * Form2.Height / 60

Print i

Next

' ve do thi trong khoang -3 den 3 doi voi gia tri cua x va -30 den 30 doi voi gia tri cau y

i = 0

For i = 0 To 500

x = -3 + i * 6 / 500

y = a * b * x ^ 2 + a * x

Form2.Line -((x + 3) * Form2.Width / 6, Form2.Height - (y + 30) * Form2.Height / 60)

Next

'tinh cuc tri

' y' = 2abx + a

If a * b = 0 Then

Form1.Text3 = "k0 ton tai"

Else

x = -1 / (2 * b)

y = a * b * x ^ 2 + a * x

Form1.Text3 = y

End If

End Sub