What does a.x mean in c++

In C, "a.x" accesses member variables or member functions of class or structure a through the dot operator ".". Member variables return their values ​​and member functions perform calls. Access qualifiers control member access rights.

a.x in c

In C, "a.x" means the name x in class or structure a member variables or member functions. The "." (dot) operator is used to access members of an object.

Member variables

If x is a member variable, a.x returns the value of the variable. For example:

<code class="cpp">class Point {
public:
    int x;
    int y;
};

Point p;
p.x = 10;
cout << p.x; // 输出 10</code>

Member function

If x is a member function, a.x() calls the function. For example:

<code class="cpp">class Shape {
public:
    int area() { return 0; }
};

Shape s;
cout << s.area(); // 输出 0</code>

Access Qualifier

Access qualifiers (such as public, private, protected) determine where members can be accessed. If x is a private member, it can only be accessed within the class.

Example

The following is an example of using a.x to access member variables and member functions:

<code class="cpp">class Person {
public:
    string name;
    int age;

    void greet() { cout << "Hello, my name is " << name << endl; }
};

Person p;
p.name = "John";
p.age = 25;
p.greet(); // 输出 "Hello, my name is John"</code>

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