(Health application: B M I ) Revise Listing 3.5,...

Key Concepts

Conditional Statements for Health Interpretation

Conditional statements are used in the BMI application to interpret the computed BMI value and to classify it into categories such as 'Underweight', 'Normal', 'Overweight', or 'Obese'. This logic helps in providing immediate feedback based on the BMI result and is a fundamental programming concept in decision-making processes.

User Input Handling in Java

Handling user input is an essential programming concept demonstrated in this application. In Java, this typically involves using the Scanner class to capture input from the console. Correctly obtaining and processing these inputs, including parsing integers or doubles as necessary, is critical for interactive programs that rely on user-provided data.

Unit Conversion

Unit conversion is a key concept in this problem because inputs such as pounds, feet, and inches must be converted to metric units (kilograms and meters) to accurately compute the BMI. This involves converting weight from pounds to kilograms and height from feet and inches to meters, which is a common task in programming to ensure that calculations use consistent and correct units.

Body Mass Index (BMI) Calculation

BMI is a widely used measure for assessing body fat based on a person's weight in relation to their height. In programming problems like this, BMI is computed by converting weight and height into appropriate units (typically kilograms and meters) and then applying the formula: BMI = weight (kg) / [height (m)]². This concept is central to health applications aimed at evaluating whether an individual is underweight, normal, overweight, or obese.

Transcript

00:01 In this video, we will create a program that calculates bmi by revising the listing 3 .4, compute, and interpret bmi .java.

00:10 To let the user enter weight, feet, and inches, for example, if a person is 5 feet 10 inches, they will enter 5 for feet and then space 10 for inches.

00:24 I've already defined our class as well as the main method within it.

00:27 I've also imported java .util .scanner since we know we'll be taking user input.

00:35 So the first thing we can go ahead and do is go into our main method and create a new scanner object named input by calling scanner with the argument system .in, which allows keyboard input to be read from inside of our java application.

00:59 The next thing we want to do is use system .0.

01:04 Println, since we'll be prompting the user to enter their weight in pounds, so we can say enter weight in pounds.

01:30 After this, we'll want to prompt the user to enter their height in inches.

01:37 As stated by prompt for this question, i'm just.

01:47 Just going to copy and paste this statement to the user, prompting them to first enter the height in terms of feet followed by a space and then inches.

02:16 Now after this, we're going to want to store both the feet and the inches separately, so we can do double feet equals and input.

02:34 Next double.

02:37 And then after this, since there's a space, after the input of feet, we'll do double inches equals input.

02:47 The next double as well.

02:52 After this, we'll get our height.

02:55 So we can calculate the height and declare variable.

03:01 So we're going to do inches plus feet times 12.

03:07 So we're converting our feet to inches and then adding the inches.

03:17 So at this point we have our height.

03:20 The next thing we're going to want to do is declare two constant variables because your constant we're going to use final before double.

03:40 And our constant is going to be kilograms per pound.

03:46 Capitalization with underscores is the appropriate way to name our constant.

04:00 This is just what we do to let a user reading our program know immediately.

04:14 Oh, this is a constant.

04:16 So it's more recognizable with the capital.

04:26 Next, we have meters per inch, 0 .0.

04:32 To 5 -4.

04:34 So now we have both of our constants because when we compute bmi, we're going to want to get our weight in kilograms, as well as our height in meters...

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