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Mathematical operations form an integral part of computer programming. In VB2013, we can write code to instruct the computer to perform mathematical calculations. By writing appropriate VB code, we can create applications that are able to solve complex mathematical problems.
Table 11.1: Mathematical Operators
|Mod||Modulus(returns the remainder of an integer division)||15 Mod 4=3|
|\||Integer Division(discards the decimal places)||19/4=4|
In this example, we insert two text boxes, four labels, and a button. Click the button and enter the code as shown below. When you run the program, it performs four basic arithmetic operations and displays the results on the four labels.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim num1, num2, difference, product, quotient As Single num1 = TextBox1.Text num2 = TextBox2.Text sum=num1+num2 difference=num1-num2 product = num1 * num2 quotient=num1/num2 Label1.Text=sum Label2.Text=difference Label3.Text = product Label4.Text = quotient End Sub
This program employs the Pythagoras Theorem to calculate the length of hypotenuse c given the length of the adjacent side a and the opposite side b. For those of you who have forgotten the formula for the Pythagoras Theorem, it is written as
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim a, b, c As Single a = TextBox1.Text b = TextBox2.Text c=(a^2+b^2)^(1/2) Label3.Text=c End Sub
Example 11.3: BMI Calculator
A lot of people are obese now and it could affect their health seriously. Obesity has proven by the medical experts to be one of the main factors that bring many adverse medical problems, including the cardiovascular disease. If your BMI is more than 30, you are considered obese. You can refer to the following range of BMI values for your weight status.
Underweight = <18.5
Normal weight = 18.5-24.9
Overweight = 25-29.9
Obesity = BMI of 30 or greater
To calculate your BMI, you don’t have to consult your doctor, you can simply use a calculator or a DIY computer program, this is exactly what we are showing you here. The BMI calculator is a Visual Basic program that can calculate the body mass index or BMI of a person based on his or her body weight in kilogram and the body height in meter. BMI can be calculated using the formula weight/( height )^2, where weight is measured in kg and height in meter. If you only know your weight and height in lb and feet, then you need to convert them to the metric system.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArsgs) Handles Button1.Click Dim height, weight, bmi As Single height = TextBox1.Text weight = TextBox2.Text bmi = (weight) / (height ^ 2) Label4.Text = bmi End Sub
The output is shown in the Figure 11.1 below. In this example, your height is 1.80m( about 5 foot 11),your weight is 75 kg( about 168Ib), and your BMI is about 23.14815. The reading suggests that you are healthy. (Note; 1 foot=0.3048, 1 lb=.45359237 kilogram)
From the above examples, you can see that writing visual basic 2013 code that involves arithmetic operations is relatively easy. Here are more arithmetic projects you work on:
Area of a triangle
Area of a rectangle
Area of a circle
Volume of a cylinder
Volume of a cone
Volume of a sphere
Sum of angles in polygons
Conversion of lb to kg
Conversion of Fahrenheit to Celsius