const的思考[5]

                      mutable int test;   file://这里处理！
               }；
           2）强制转换：const_cast
               class a
               {
               public:
                      a(int i=0):test(i)        { }
                      void setvalue(int i)const
                      { const_cast <int>(test)=i; }//这里处理！
               private:
                      int test;  
               }；
            3）灵活的指针：int*
               class a
              {
               public:
                      a(int i=0):test(i)        { }
                      void setvalue(int i)const
                      { *test=i; }
               private:
                      int* test;   file://这里处理！
               }；
            4）未定义的处理
              class a
              {
               public:
                      a(int i=0):test(i)        { }
                      void setvalue(int i)const
                      { int *p=(int*)&test; *p=i; }//这里处理！
               private:
                      int test;  
               }；
                注意，这里虽然说可以这样修改，但结果是未定义的，避免使用！
             5）内部处理：this指针
              class a
              {
               public:
                      a(int i=0):test(i)        { }
                      void setvalue(int i)const