爲什麼我沒有得到下面的代碼需要解釋的輸出？

-3

public class Triangle 
{ 

    float length; //declared length as float 
    float breadth; //declared breadth as float 
    public static void main(String[] args) 
    { 
     Triangle Triangle1 = new Triangle(); 
     Triangle Triangle2 = new Triangle(); 

     float area; //declared area as float 

     Triangle1.length = 11; 
     Triangle1.breadth = 22; 
     Triangle2.breadth = 15; 
     Triangle2.length = 20; 

     area = 0.5 * Triangle1.length * Triangle1.breadth; 
     System.out.println("The area of Triangle is" + " " + area); 

     area = 0.5 * Triangle2.length * Triangle2.breadth; 
     System.out.println("The area of Triangle is" + " " + area); 

    } 
}

我已經宣佈該區域爲浮動較早，我得到complie時間錯誤，當我改變它成雙，我可以得到下面的輸出。需要知道爲什麼...？爲什麼我沒有得到下面的代碼需要解釋的輸出？

float area;

Error:(24, 49) java: incompatible types: possible lossy conversion from double to float 
Error:(27, 49) java: incompatible types: possible lossy conversion from double to float

來源

2016-08-24 Ajay Kumar

錯誤是告訴你爲什麼用簡單的英語。 –

'double'是64位，'float'是32位。您將乘以兩個64位數並嘗試將結果存儲在32位中。 –

在15秒3個不同的正確答案^^ – mayha

您的代碼有幾個錯誤。

請保留命名約定。類從大寫字母開始，變量不要。所以.. Triangle triangle1 = new Triangle()。
爲了保留所有數據在float，您需要將float中的所有數字相乘。 0,5默認爲double，具有比float更大的小數精度。有兩種方法來解決這個問題：

使用F或f指標（我推薦一個大寫）說，你與float工作。否則的Java unserstands它作爲double：

area = 0.5F * triangle1.length * triangle1.breadth;

或鑄所有resutl到float：

area = (float) 0.5 * triangle1.length * triangle1.breadth;

來源

2016-08-24 13:09:35

我沒有得到第一個評論 –

我沒有得到您的答覆。你有什麼不明白？ –

正如你所提到的，類以capitlal字母和用小寫字母創建的對象開始。 –

在Java中的一樣2.553默認號碼是雙所以當你

area = 0.5 * Triangle1.length * Triangle1.breadth;

你正在做雙*浮動*浮動。如果你想使用0.5作爲浮動你需要數字後加字母˚F所以你的代碼將是這樣的：

area = 0.5f * Triangle1.length * Triangle1.breadth;

來源

2016-08-24 13:09:18 pr0gramist

-1

執行此操作。

public class Triangle 
{ 
    float length; //declared length as float 
    float breadth; //declared breadth as float 

    public static void main(String[] args) 
    { 

     Triangle Triangle1 = new Triangle(); 
     Triangle Triangle2 = new Triangle(); 

     float area; //declared area as float 

     Triangle1.length = 11; 
     Triangle1.breadth = 22; 
     Triangle2.breadth = 15; 
     Triangle2.length = 20; 

     area = (float)0.5 * Triangle1.length * Triangle1.breadth; 
     System.out.println("The area of Triangle is" + " " + area); 

     area = (float)0.5 * Triangle2.length * Triangle2.breadth; 
     System.out.println("The area of Triangle is" + " " + area); 
    } 
}

來源

2016-08-24 13:09:26 Jared

你有兩個選擇：

浮點型變量的每一個初始化後添加f，像Triangle1.length = 11f;

因此，代碼變爲：

public class Triangle { 

float length; // declared length as float 
float breadth; // declared breadth as float 

public static void main(String[] args) { 

    Triangle Triangle1 = new Triangle(); 
    Triangle Triangle2 = new Triangle(); 

    float area; // declared area as float 

    Triangle1.length = 11f; 
    Triangle1.breadth = 22f; 
    Triangle2.breadth = 15f; 
    Triangle2.length = 20f; 

    area = 0.5f * Triangle1.length * Triangle1.breadth; 
    System.out.println("The area of Triangle is" + " " + area); 

    area = 0.5f * Triangle2.length * Triangle2.breadth; 
    System.out.println("The area of Triangle is" + " " + area); 

}

}

充分利用area可變double類型：

您的代碼從而變成：

public class Triangle { 

float length; // declared length as float 
float breadth; // declared breadth as float 

public static void main(String[] args) { 

    Triangle Triangle1 = new Triangle(); 
    Triangle Triangle2 = new Triangle(); 

    double area; // declared area as float 

    Triangle1.length = 11; 
    Triangle1.breadth = 22; 
    Triangle2.breadth = 15; 
    Triangle2.length = 20; 

    area = 0.5 * Triangle1.length * Triangle1.breadth; 
    System.out.println("The area of Triangle is" + " " + area); 

    area = 0.5 * Triangle2.length * Triangle2.breadth; 
    System.out.println("The area of Triangle is" + " " + area); 

}

}

希望它有幫助！

來源

2016-08-24 13:17:47

爲什麼我沒有得到下面的代碼需要解釋的輸出？

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