基本的Java，在方法之間傳遞數據

Question

我是Java的新手，試圖製作一個基本的體重計算器。 我的問題是我需要問的問題，轉換測量，然後將其傳遞給另一種方法，然後以單獨的方法顯示結果。 我已經在下面添加了我的代碼，但每次都收到1.0返回的答案。

import java.util.Scanner; 

public class calcBMI { 

    public static void main(String[] args) 
    { 
     Scanner keyboard = new Scanner(System.in); 

     System.out.print("Enter weight in pounds: "); 
     double weightInPounds = keyboard.nextDouble(); 
     double weightInKg = (weightInPounds/2.2); 

     System.out.print("Enter height in inches: "); 
     double heightInInches = keyboard.nextDouble(); 
     double heightInMeters = (heightInInches/0.254); 
     double resultBMI = 1; 

     displayResults(resultBMI); 
    } 

    public static double bodyMassIndex(double weightInKg, double 
    heightInMeters) 
    { 
     double resultBMI = weightInKg/Math.pow(heightInMeters, 2) * 1.375; 

     return resultBMI; 
    }   

    public static void displayResults(double resultBMI) 
    { 

     System.out.printf("The calculated body mass index was: " + resultBMI); 

     System.out.println(); 
    } 
} 

---

更新代碼，現在越來越; 磅輸入重量：180 以英寸輸入高度：68 計算的身體質量指數是：1.1415618118905313E -5- 生成成功（總時間：3秒）

import java.util.Scanner; 

public class calcBMI { 

    public static void main(String[] args) 
    { 
     Scanner keyboard = new Scanner(System.in); 

     System.out.print("Enter weight in pounds: "); 
     double weightInPounds = keyboard.nextDouble(); 
     double weightInKg = (weightInPounds/2.2); 

     System.out.print("Enter height in inches: "); 
     double heightInInches = keyboard.nextDouble(); 
     double heightInMeters = (heightInInches/0.0254); 


     displayResults(bodyMassIndex(weightInKg, heightInMeters)); 
    } 

public static double bodyMassIndex(double weightInKg, double heightInMeters) 
    { 
     return (weightInKg/Math.pow(heightInMeters, 2)); 
    }   

public static void displayResults(double resultBMI) 
    { 

     System.out.printf("The calculated body mass index was: " + resultBMI); 

     System.out.println(); 
    } 
} 

Answer 1

你得到1.0因爲你硬編碼它。

更改此：

double resultBMI = 1; 

要：

double resultBMI = bodyMassIndex(weightInKG, heightInMeters); 

---

順便問一下，你也可以有直接的方法返回BMI並沒有無需通過乘以1.375因爲您已經提供KG的體重：

public static double bodyMassIndex(double weightInKg, double heightInMeters) 
{ 
    return (weightInKg/(heightInMeters*heightInMeters)); 
} 

---

添加上：

你從英寸轉換爲米是錯誤的爲好。它應該是：

double heightInMeters = (heightInInches * 0.0254); 

Answer 2

您還沒有調用bodyMassIndex方法在你的代碼中。更改

displayResults(resultBMI); 

到

displayResults(bodyMassIndex(weightInKg, heightInMeters)); 

resultBMI等於，所以當然的輸出將永遠是：

"The calculated body mass index was: 1" 

全碼：

public static void main(String[] args) { 

    System.out.print("Enter weight in pounds: "); 
    double weightInPounds = keyboard.nextDouble(); 
    double weightInKg = (weightInPounds/2.2); 

    System.out.print("Enter height in inches: "); 
    double heightInInches = keyboard.nextDouble(); 
    double heightInMeters = (heightInInches/0.254);   

    // You can get rid of the resultBMI variable 
    displayResults(bodyMassIndex(weightInKg, heightInMeters)); 
}