'::' Please tell me what this sign means

Question

Hello, I am a Korean student learning C++
While using C++, I have a few questions and I have a question.
I think M/S's answer will be of great help to me, so please let me know in detail.

1. '::' I want to know what this sign means
2. Please tell me why the '::' is the glyph and why it wasn't the other glyph
   For example, please tell me if you have used a pattern like '##' or a pattern like ' ` ' somewhere else.
3. C++ developers tell us why they made object-oriented languages

Thank you for reading this article during your busy time.

Answer 1

object oriented programing became popular in the 60's.

https://en.wikipedia.org/wiki/Object-oriented_programming

in the early 80s, there were two projects to bring classes, inhertance and polymorphism to C. Both languages want to pure supersets of C. so in both cases new syntax symbols were added.

• objective-c: designed by Brad Cox mostly influenced by smalltalk, it added smalltak style classes and inheritance, Use used smalltalk syntax to send messages to object, [obj message], and @ prefix.
• c++: designed by Bjarne Stroustrup, mostly influenced by simula-67. simula used the dot notation to access object properties and virtual methods. C++ implemented polymorphism without runtime binding (v-tables instead). the lack of runtime binding has led to much of the complexity of C++ requiring templates, etc.

in C++, to allow polymorphism, two classes can define the same method name. to distinguish which Class method your code is referring to the syntax <classname>::<method name> is used. when namespaces were added, this was generalized to scoping.