Hello all. This is our first tutorial after a long time of being under maintenance. In this tutorial we are going to learn how to program an app in visual basic that can solve quadratic equations.
A quadratic equation is a second-degree polynomial that has the form “ax^2 + bx + c = 0.” The “a,” “b” and “c” are the constants and “x” is the variable. When you solve a quadratic equation, you must have the values of the constants and solve for x, which always yields two values, called the “roots.” In Visual Basic, you can write a program or function that prompts the user to enter the a, b and c values, find the roots and then display the values on the form.
- Add 3 textbox and Change the name of them to TxtA1 and TxtB1 TxtC1
- Add a label and name it to LblM1
- Add 6 labels and name them to Labelx , Labelx2 , lbldelta2 , lbldelta , LblAns2 and LblAns1
- Set the visible of these 6 labels to False
- Add a button and name it to Cmd1
- Now just paste this code. ( I explained the codes function in green line)
Private Sub Cmd1_Click() Dim delta As Double, a As Double, b As Double, c As Double If TxtA1.Text = "" Or TxtB1.Text = "" Or TxtC1.Text = "" Then MsgBox ("Please fill all informations") Else a = Val(TxtA1.Text) b = Val(TxtB1.Text) c = Val(TxtC1.Text) delta = (b * b) - (4 * a * c) lbldelta.Caption = delta 'it shows the Amount of delta lbldelta.Visible = True LblM1.Caption = TxtA1.Text + "x + " + TxtB1.Text + "X +" + TxtC1.Text 'This is for showing the form of equation lbldelta2.Visible = True If (delta > 0) Then 'so we have 2 roots LblAns1.Caption = Str(((-1 * b) + Sqr(delta)) / (2 * a)) LblAns2.Caption = Str(((-1 * b) - Sqr(delta)) / (2 * a)) 'lets make the roots visible LblAns1.Visible = True LblAns2.Visible = True Labelx.Visible = True Labelx2.Visible = True End If If (delta = 0) Then 'then we just have 1 root LblAns1.Caption = (-1 * b) / (2 * a) LblAns1.Visible = True Labelx.Visible = True ' we dont have 2 roots so we have to set the visible of x2 and Ans2 False LblAns2.Visible = False Labelx2.Visible = False End If If (delta < 0) Then LblAns1.Caption = "No Answer" LblAns1.Visible = True LblAns2.Visible = False Labelx.Visible = False Labelx2.Visible = False End If End If End Sub
Coded By: Danial Nikbin