为什么我没有得到下面的代码需要解释的输出？

-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); 

    } 
}

我已经宣布该区域为浮动较早，我得到complie时间错误，当我改变它成双，我可以得到下面的输出。需要知道为什么...？为什么我没有得到下面的代码需要解释的输出？

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

来源

2016-08-24 Ajay Kumar

错误是告诉你为什么用简单的英语。 –

'double'是64位，'float'是32位。您将乘以两个64位数并尝试将结果存储在32位中。 –

在15秒3个不同的正确答案^^ – mayha

您的代码有几个错误。

请保留命名约定。类从大写字母开始，变量不要。所以.. Triangle triangle1 = new Triangle()。
为了保留所有数据在float，您需要将float中的所有数字相乘。 0,5默认为double，具有比float更大的小数精度。有两种方法来解决这个问题：

使用F或f指标（我推荐一个大写）说，你与float工作。否则的Java unserstands它作为double：

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

或铸所有resutl到float：

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

来源

2016-08-24 13:09:35

我没有得到第一个评论 –

我没有得到您的答复。你有什么不明白？ –

正如你所提到的，类以capitlal字母和用小写字母创建的对象开始。 –

在Java中的一样2.553默认号码是双所以当你

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

你正在做双*浮动*浮动。如果你想使用0.5作为浮动你需要数字后加字母˚F所以你的代码将是这样的：

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

来源

2016-08-24 13:09:18 pr0gramist

-1

执行此操作。

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); 
    } 
}

来源

2016-08-24 13:09:26 Jared

你有两个选择：

浮点型变量的每一个初始化后添加f，像Triangle1.length = 11f;

因此，代码变为：

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可变double类型：

您的代码从而变成：

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); 

}

}

希望它有帮助！

来源

2016-08-24 13:17:47

为什么我没有得到下面的代码需要解释的输出？

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