C++学习日志49-----自定义异常类

---

一、自定义异常类

#include<iostream>
#include<exception>
#include"Vec3D.h"
using std::cout;
using std::endl;
//任务4:在主函数中创建Vec3D对象并调用[]制造越界问题
//捕获异常并输出异常中的信息
int main()
{
	Vec3D v1{ 1.2,3.2,4.3 };
	try
	{
		cout << v1[4];
	}
	catch (std::exception& e)
	{
		cout << "Exception: " << e.what() << endl;
		if (typeid(e) == typeid(RangeException))
		{
			auto r = dynamic_cast<RangeException&>(e);
			cout << "Vector dimension : " << r.getDimension() << endl;
			cout << " I ndex:" << r.getIndex() << endl;

		}
	}




}

结果如上图所示。

二、相关文件

#pragma once
#include<array>
#include"RangeException.h"
//任务1:创建Vec3D类，用array保存向量成员

//任务3:实现Vec3D::operator[](const int d=index)
//当index越界时，抛出RangeException 的对象
class Vec3D
{
private:
	std::array<double, 3> v{ 1.0,1.0,1.0 };
public:
	Vec3D() = default;
	Vec3D(double x, double y, double z)
	{
		v[0] = x;
		v[1] = y;
		v[2] = z;
	}
	double& operator[](const int index)
	{
		if (index >= 0 && index <= 2)
		{
			return v[index];
		}
		else
		{
			throw RangeException(3, index);
		}
	}
};

#pragma once
#include<iostream>
#include<exception>
//任务2:创建RangeException 类
//定义构造函数 RangeException(std::size_t dimension,const int index)
class RangeException:public std::exception
{
private:
	std::size_t dimension{ 3 };
	int index{ 0 };
public:
	RangeException(std::size_t dimension, const int index)
	{
		this->dimension = dimension;
		this->index = index;
	}
	std::size_t getDimension()
	{
		return dimension;
	}
	int getIndex()
	{
		return index;
	}


};