#8 BMI Calculator app

畫面呈現：

畫面包含：
1. 建立IBOutlet：
・顯示身高體重數值之TextField
・顯示BMI數字結果之Label
・顯示BMI範圍結果之Label

2. 建立IBAction：
・收鍵盤的手勢
・UIButton 設定BMI calculation

import UIKit

class BmiViewController: UIViewController {
    @IBOutlet weak var heightTextField: UITextField!
    @IBOutlet weak var weightTextField: UITextField!
    @IBOutlet weak var bmiLabel: UILabel!
    @IBOutlet weak var resultLevel: UILabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }
        // 手勢收鍵盤
    @IBAction func keyboard(_ sender: Any) {
        view.endEditing(true)
    }
    @IBAction func calculate(_ sender: Any) {
        
        if let heightText = heightTextField.text,
           let weightText = weightTextField.text,
           let height = Double(heightText),
           let weight = Double(weightText) {
            
               let heightMeter = height / 100
      //代入BMI公式，將結果顯示於Label中
               let bmi = weight / (heightMeter * heightMeter)
               bmiLabel.text = String(format: "%.2f", bmi)
      //BMI數值範圍顯示之文字
        if bmi < 18.5 {
            resultLevel.text = "Underweight"}
            else if bmi > 18.5, bmi < 24.9 {
            resultLevel.text = "Healthy Weight"
            }else if bmi > 25.0, bmi < 29.9{
            resultLevel.text = "Overweight"
            }else{ resultLevel.text = "Obese" }
      }
    }

結果呈現：

參考資料：

BMI Calculator