const修饰this指针的用法

#include <iostream>
#include <string>

using namespace std;

class Base
{
};

class Exception : public Base
{
    int m_id;
    string m_desc;
public:
    Exception(int id, string desc)
    {
        m_id = id;
        m_desc = desc;
    }
    
    int id() const
    {
        return m_id;
    }
    
    string description() const
    {
        return m_desc;
    }
};


/*
    假设： 当前的函数式第三方库中的函数，因此，我们无法修改源代码
    
    函数名： void func(int i)
    抛出异常的类型： int
                        -1 ==》 参数异常
                        -2 ==》 运行异常
                        -3 ==》 超时异常
*/
void func(int i)
{
    if( i < 0 )
    {
        throw -1;
    }
    
    if( i > 100 )
    {
        throw -2;
    }
    
    if( i == 11 )
    {
        throw -3;
    }
    
    cout << "Run func..." << endl;
}

void MyFunc(int i)
{
    try
    {
        func(i);
    }
    catch(int i)
    {
        switch(i)
        {
            case -1:
                throw Exception(-1, "Invalid Parameter");
                break;
            case -2:
                throw Exception(-2, "Runtime Exception");
                break;
            case -3:
                throw Exception(-3, "Timeout Exception");
                break;
        }
    }
}

int main(int argc, char *argv[])
{
    try
    {
        MyFunc(11);c
    }
    catch(const Exception& e)
    {
        cout << "Exception Info: " << endl;
        cout << "   ID: " << e.id() << endl;
        cout << "   Description: " << e.description() << endl;
    }
    catch(const Base& e)
    {
        cout << "catch(const Base& e)" << endl;
    }
    
    return 0;
}