简单的Java程序......执行错误。 [英] Simple Java program ...Exeption Error.

问题描述

您好，

我是初学者，刚刚开始进行java编程，通过练习我在三角区域示例中遇到了一个错误，无法解决。我尝试了一切，但我没有得到它。任何人都可以告诉我为什么这个错误会出现在以下程序中。

Hello,
I beginner and just started java programming and by doing its practice I got an error in the Example of Area of Triangle which couldn't solved out. I tried everything but I don't get it. Can anybody tell me why this error comes in following program.

/*Program to calculate area of a triangle when three sides are passed as input .*/
class Area
{
    public static void main(String args[])
    {
        int s,sum=0,n;
        double area;
         n=args.length;
        int []a=new int [n];    //Declaration of array to define three sides of a triangle.
        for(int i=0;i<=n;i++)
        {
            if(n<=3)
            {
                a[i]=Integer.parseInt(args[i]);
                sum=sum+a[i];
            }
            else
            {
                System.out.println("You Should Enter Only Three Values");
                break;
            }
        }
        if(n<=3)
        {
            s=sum/2;
            area=Math.sqrt(s*(s-a[1])*(s-a[2])*(s-a[3]));
                        System.out.println("Area = "+area);
        }
        }
}

之后，我使用了javac编译器：



> javac area.java

> java area 3 5 6



之后出现以下错误。



>线程中的异常主java.lang.ArrayIndexOutOfBoundsException：3在Area.main< Area.java:14>



谢谢。

And after that, I used javac compiler:

>javac area.java
>java area 3 5 6

After That the following error comes.

>" Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3 at Area.main<Area.java:14>

Thanks.

推荐答案

除了谢尔盖的回答，这部分代码也被打破了：

In addition to Sergey's answer, this part of code is broken too:

Quote：

if（n< = 3）

{

s = sum / 2;

area = Math.sqrt（s *（sa [1]）*（sa [2]）*（sa [3]））;

System.out.println（Area =+ area）;

}

if(n<=3)
{
s=sum/2;
area=Math.sqrt(s*(s-a[1])*(s-a[2])*(s-a[3]));
System.out.println("Area = "+area);
}

例如，如果 n = 2 那么如果 条件评估为为真并执行代码块，但都是 a [2] 和 a [3] 不存在。

For instance, if n=2 then the if condition evaluates to true and code block is executed, but both a[2] and a[3] don't exist.

最大 i ， args [i] 不存在，因为用户没有提供这么多参数。

这是因为你的错误：

For maximum i, args[i] does not exist, because the user did not provide so many arguments.
It happened because of your bug:

for(int i=0;i<=n;i++)

可以通过以下方式修复：

Can be fixed by writing:

for (int i=0; i<n; i++)

-SA

我解决了。感谢您的帮助。



编辑的程序是，

I solved it. Thanks to help.

The Edited Program is,

/*Program to calculate area of a triangle when three sides are passed as input .*/
class Area
{
    public static void main(String args[])
    {
        int s,sum=0,n,ss,m=1;
        double area;
        n=args.length;
        int []a=new int [n];    //Declaration of array to define three sides of a triangle.
        for(int i=0;i<n;i++)
        {
            if(n==3)
            {
                a[i]=Integer.parseInt(args[i]);
            }
            else
            {
                System.out.println("Please Enter Only Three Values");
                break;
            }
            sum=sum+a[i];
        }
        if(n==3)
        {
            s=sum/2;
            for(int i=0;i<n;i++)
            {
            ss=(s-a[i]);           //ss Assigns s-a[1] to s-a[3] separately 
            m=m*ss;                //Passing value of ss to m 
            }
            area=Math.sqrt(s*m);   
                        System.out.println("Area of Triangle = "+area);
        }
        }
}

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