版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/XUCHEN1230/article/details/84993120
class Person1
{
public:
Person1()
{
//构造中修改属性:
//this永远指向本体
//相当于:Person *const this
//所以,在const的修饰下,this指针只能指向Person,不能指向别人;
//但是可以修改指针指向的值;
this->m_A = 0;
this->m_B = 0;
}
void showInfo() const //此时不能修改this的值,这种函数叫做常函数;
{
//不允许修改指针的指向;
//this->m_A = 1000;
cout << "m_A" << this->m_A << endl;
cout << "m_B" << this->m_B << endl;
}
int m_A;
int m_B;
};
class Person2
{
public:
Person2()
{
//构造中修改属性:
//this永远指向本体
//相当于:Person *const this
//所以,在const的修饰下,this指针只能指向Person,不能指向别人;
//但是可以修改指针指向的值;
this->m_A = 0;
this->m_B = 0;
}
void showInfo() const //此时不能修改this的值,这种函数叫做常函数;
{
//this->m_A = 1000;//修改m_A会报错。
this->m_B = 1000;//不会报错;因为加了mutable关键字;
cout << "m_A" << this->m_A << endl;
cout << "m_B" << this->m_B << endl;
}
void show2()
{
}
int m_A;
mutable int m_B; //现在要求就算是常函数,还是要执意修改;
};
void test01()
{
Person2 p1;
p1.showInfo();
}
//结果:m_A0 m_B1000
//常对象:不允许修改内部属性
void test02()
{
const Person2 p2;
//p2.m_A = 1000; //会报错,提示必须为可修改左值;
//但是可以调用:
cout << p2.m_A << endl;
//p2.show2(); //会报错
//常对象,可以调用常函数;
//常对象 不能修改 属性;
}
int main()
{
test01();
test02();
return 0;
}