The difference between :: and . in c++

The difference between :: and . in C

Answer:
The :: and . in C are two different operators. Use For accessing class members and global members.

Detailed explanation:

1. :: (scope parsing operator)

• is used to access the global Members, including variables, functions and types declared outside the class.
• can be used to resolve naming conflicts, such as when the class name is the same as the global variable name.
• Syntax: :: member name;

2. . (member access operator)

• is used to access classes Members, including data members and member functions.
• Must be used to access members from class instances.
• Syntax: Object.Member name;

Difference:

• Access scope::: Access global members, .Access class members.
• Naming conflict: :: Can resolve naming conflict, . cannot.
• Instance dependency: . Must be used to access members from class instances, :: is not required.

Example:

Access global variables:

<code class="cpp">int global_var = 10;
cout << ::global_var; //输出 10</code>

Access class data members:

<code class="cpp">class MyClass {
public:
    int data_member = 20;
};

MyClass object;
cout << object.data_member; //输出 20</code>

Resolving naming conflicts:

<code class="cpp">class MyClass {
public:
    static int global_var = 30;
};

int global_var = 40;
cout << ::MyClass::global_var; //输出 30</code>

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