Explanation

In this problem, you will learn comprehensive programming that reads multiple different data types with Scanner class, performs calculations and makes judgments.

nextDouble() Method

nextDouble() is a method that reads decimal numbers (double type). It's used for input that requires decimals, such as height and weight.

Implementation Example

import java.util.Scanner;

Public class Solution {
  Public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
// Read each data
String name = sc.nextLine();
Double height = sc.nextDouble();
Double weight = sc.nextDouble();
Int age = sc.nextInt();

// Calculate BMI
Double bmi = weight / (height * height);

// Determine status
String status;
If (bmi < 18.5) {
  Status = "Underweight";
} else if (bmi < 25.0) {
  Status = "Normal";
} else {
  Status = "Overweight";
}

// Display health check card
System.out.println("===== Health Check Card =====");
System.out.println("Name: " + name);
System.out.println("Height: " + height + "m");
System.out.println("Weight: " + weight + "kg");
System.out.println("Age: " + age + " years old");
System.out.printf("BMI: %.1f%n", bmi);
System.out.println("Status: " + status);
System.out.println("=============================");

  }
}

Key Points

• nextDouble(): Method to read decimal numbers
• double type calculation: Calculations with decimals result in decimals
• printf(): Output with controlled decimal places (%.1f for one decimal place)
• Multiple conditions: Step-by-step judgment using if-else if

Meaning of BMI Calculation

BMI is an index showing the balance between weight and height. Through this calculation, you learn how to create practical programs.