I do not know why but this code works, what does this record }r; and how it works ? can in this way be declared a global object class ?
#include <iostream>
class А
{
public:
А()
{
std::cout << "Hello World";
}
}r;
int main()
{
}
That declares a global variable named r that is of type A.
It's the same as
class A { ... };
A r;
int main() { ... }
can in this way be declared a global object class ?
Um, yeah! Basically, r there is a global variable of type А. C++ has inherited from C a certain syntax that enables you to declare variables after a class/struct definition. You can often see from C something like
struct vertex {
float x, y;
} my_vertex; // Declares a variable of type vertex
In C++, a struct is the same as class with the exception of the default access specifier.
You might have wondered what the semicolon is for after class definitions. So basically a class defined as
class my_class {};
with the braces immediately proceeded by a semicolon declares no variables.
You can also declare more than one variables by delimiting them with the comma operator.
class my_class {} x, y, z;
It Create one instance of class A with name r. It's pretty much the same as doint int r; Which would make a global int on that position.
maybe this helps you for a better understanding.
C++: Declare a global class and access it from other classes?
br
