Why is the result of my program always underweight in BMI? - vb.net

Question

Here is my code:
Dim Weight, Height, Bmi_value As Integer
Weight = TextBox1.Text
Height = TextBox2.Text
Bmi_value = (Weight / Height ^ 2)
TextBox3.Text = Bmi_value
Select Case Bmi_value
Case 0.0 To 18.5
TextBox4.Text = "Underweight"
Case 18.6 To 24.9
TextBox4.Text = "Normal"
Case 25.0 To 29.9
TextBox4.Text = "Overweight"
Case Is >= 30.0
TextBox4.Text = "Obese"
End Select
End Sub

Answer 1

This is your code fixed:
'You were using Integer instead of Double
Dim Weight, Height, Bmi_value As Double
If you want to take the value from the textBoxes, you have to covert it to Double.
Weight = Convert.ToDouble(TextBox1.Text)
Height = Convert.ToDouble(TextBox2.Text)
'Better to call the right function Math.Pow()
Bmi_value = (Weight / Math.Pow(Height, 2))
'You have to convert it to String
TextBox3.Text = Convert.ToString(Bmi_value)
Select Case Bmi_value
Case 0.0 To 18.5
TextBox4.Text = "Underweight"
Case 18.6 To 24.9
TextBox4.Text = "Normal"
Case 25.0 To 29.9
TextBox4.Text = "Overweight"
Case Is >= 30.0
TextBox4.Text = "Obese"
End Select
End Sub
There was alot of error in this code:
First: don't declare var as integer if you need decimal value, like with the BMI calculation.
Second: always convert your value to the right type if you are getting them from TextBox or if you want to print them inside a TextBox

Answer 2

Dim dblWeight As Double, dblHeight As Double, dblBMI As Double
dblWeight = CDbl(TextBox1.Text) 'assumes lbs.
dblHeight = CDbl(TextBox2.Text) 'assumes inches
On Error GoTo 0
dblBMI = ((dblWeight * 703.0#) / (dblHeight * dblHeight))
TextBox3.Text = dblBMI
Select Case dblBMI
Case Is <= 18.5 : TextBox4.Text = "Underweight"
Case 18.6 To 24.9 : TextBox4.Text = "Normal"
Case 25.0# To 29.9 : TextBox4.Text = "Overweight"
Case 30.0# To 34.9 : TextBox4.Text = "Obese Class I"
Case 35.0# To 39.9 : TextBox4.Text = "Obese Class II"
Case Is >= 40.0# : TextBox4.Text = "Obese Class III"
End Select
Exit Sub
Try this, Works for me.