全局函数VS成员函数

 #include <iostream>

 using namespace std;

 class  Test
 {
 public:
     Test(int a, int b)
     {
         this->a = a;
         this->b = b;
     }
     int getA()
     {
         return a;
     }
     int getB()
     {
         return b;
     }

     Test add(Test &t2)
     {
         this->a = this->a + t2.getA();
         this->b = this->b + t2.getB();
         //return *this;
     }
     void print()
     {
         cout << "a = " << a << "  b = " << b << endl;

     }
 protected:
 private:
     int a, b;
 };

 Test add(Test &t1, Test &t2)
 {
     Test t3(t1.getA() + t2.getA(), t1.getB() + t2.getB());
     return t3;
 }

 int main()
 {
     Test t1(, );
     Test t2(, );
     //Test t3 = add(t1, t2);
     t1.add(t2);
     t1.print();

     system("pause");
     return ;
 }

成员函数隐藏了一个this指针,谁调用成员函数,this指针就指向谁,这个this指针就是指向调用成员函数的对象的首地址.

在成员函数里, *this 就是调用对象元素本身.一般用于return *this