对于我的一个类赋值,我需要创建一个创建三角形对象的类。根据几何规则,对于一个有效的三角形,任意一条边的长度应小于其他两条边的长度之和。我编写的对象构造函数类可以采用任何double,这意味着可以输入三角形的一侧,其长度比其他两个的组合长度长。这违反了三角形的几何规则(这是可以的)。但是,我想记录有多少三角形违反了几何规则,因此无法构造。
通常,您会使用try,catch块来捕获异常。但是,这里的问题是,一旦到达异常,就会跳过异常后面的对象,而不会创建它。这就产生了两个问题:第一,非法对象之后的任何合法对象都不会被创建。第二,我无法跟踪除了第一个非法对象之外有多少对象未能创建(因为其余对象被跳过)。如何重新构造代码,以便创建合法对象(即使碰到非法对象),并统计有多少合法/非法对象?我已经使用了一个定制的异常处理程序对象,我已经为三角形对象编写了这个对象,但是为了减少代码,这里没有包括它。我是一个初学者,所以对你来说显而易见的解决方案对我来说是模糊的。谢谢你的帮助。
这是我的三角测试仪代码:
public class TestTriangle {
public static void main(String[] args) throws IllegalTriangleException {
// Start of try block for creating 4 triangle objects
try {
Triangle triangle1 = new Triangle(); // create first triangle using default constructor
System.out.println(triangle1.toString()); // output the information about length of sides
// output info about perimeter and area of triangle
System.out.println("The perimeter of the triangle1 is " + triangle1.getPerimeter());
System.out.println("The area of the triangle1 is " + triangle1.getArea());
System.out.println();
Triangle triangle2 = new Triangle(3, 4, 5); // create a second triangle given sides
System.out.println(triangle2.toString());
System.out.println("The perimeter of the triangle2 is " + triangle2.getPerimeter());
System.out.println("The area of the triangle2 is " + triangle2.getArea());
System.out.println();
Triangle triangle3 = new Triangle(4, 2, 5); // create a third triangle given sides
System.out.println(triangle3.toString());
System.out.println("The perimeter of the triangle3 is " + triangle3.getPerimeter());
System.out.println("The area of the triangle3 is " + triangle3.getArea());
System.out.println();
Triangle triangle4 = new Triangle(2, 3, 7); // try to create an illegal triangle
System.out.println(triangle4.toString());
System.out.println("The perimeter of the triangle4 is " + triangle4.getPerimeter());
System.out.println("The area of the triangle4 is " + triangle4.getArea());
System.out.println();
Triangle triangle5 = new Triangle(2, 4, 9); // try to create an illegal triangle
System.out.println(triangle5.toString());
System.out.println("The perimeter of the triangle5 is " + triangle5.getPerimeter());
System.out.println("The area of the triangle5 is " + triangle5.getArea());
System.out.println();
// catch exceptions, if any
} catch (IllegalTriangleException ex) {
System.out.println("Exception: " + ex);
}
System.out.println();
System.out.println(Triangle.getNumberOfObjects() + " triangles constructed");
System.out.println(Triangle.illegalAttempts() + " triangle(s) failed to construct");
}
}
如果你需要研究的话,这里有一个类构造函数:
public class Triangle {
// declare variables for each side of the triangle
private double side1;
private double side2;
private double side3;
// declare variables to keep track of number of objects created or illegal attempts
private static int numberOfObjects = 0;
private static int illegalAttempts = 0;
// default constructor for triangle
public Triangle() {
side1 = 1.0;
side2 = 1.0;
side3 = 1.0;
numberOfObjects++;
}
// constructor for creating triangles based on length of sides
public Triangle(double newSide1, double newSide2, double newSide3) throws IllegalTriangleException {
setSides (newSide1, newSide2, newSide3);
numberOfObjects++;
}
// setter for creating triangles given the length of sides
public void setSides (double newSide1, double newSide2, double newSide3) throws IllegalTriangleException {
// According to geometric rules, in triangles, any one side should be shorter than the combined length of other two.
// Check to see if any one side is longer than the combined length of other two. If so, throw the designed exception.
if (newSide1 >= newSide2 + newSide3) {
illegalAttempts++;
throw new IllegalTriangleException(newSide1, newSide2, newSide3);
} else if (newSide2 >= newSide1 + newSide3) {
illegalAttempts++;
throw new IllegalTriangleException(newSide2, newSide1, newSide3);
} else if (newSide3 >= newSide1 + newSide2) {
illegalAttempts++;
throw new IllegalTriangleException(newSide3, newSide1, newSide2);
} else {
side1 = newSide1; // In case the geometric rule is not violated, create the sides.
side2 = newSide2;
side3 = newSide3;
}
}
// constructor for getting the number triangle created
public static int getNumberOfObjects() {
return numberOfObjects;
}
public static int illegalAttempts() {
return illegalAttempts;
}
// constructor for calculating the perimeter of triangles
public double getPerimeter() {
return side1 + side2 + side3;
}
// constructor for calculating the area of a triangle given three sides: sqrt(p*(p-a)*(p-b)*(p-c))
public double getArea() {
double perimeter = side1 + side2 + side3;
return Math.sqrt(perimeter * (perimeter - side1) * (perimeter - side2) * (perimeter - side3));
}
// create an string object giving information about the triangle
public String toString() {
return "Triangle: Side a = " + side1 + ", Side b = " + side2
+ ", Side c = " + side3;
}
}
代码的输出应该是这样的:
三角形:边a=4.0,边b=2.0,边c=5.0三角形3的周长为11.0三角形3的面积为64.48255578061404
例外:非法三角形例外:非法三角形,任意两边之和小于另一边的边1是7.0边2是2.0边3是3.0
构造了3个三角形2个三角形未能构造
1条答案
按热度按时间pb3s4cty1#
考虑到三角形初始化除了它们的值之外是相同的,一个选项可能是从try块中提取硬编码的值。如果任何一个三角形构造失败,它将被捕获、处理,然后转到下一个三角形参数集。
输出
twicelost请求了一个避免使用列表的选项。一个稍微冗长的选项是将每个三角形构造 Package 在try/catch中。