Simple Class: Path of execution.

[Pebble]

I'm teaching myself about Classes so i can start using SFML, But
Cant work out how the function at line 14 is called.
Can someone explain the logical path of this program during execution?

#include <iostream>

class FullName
{
private:
    std::string a;
    std::string b;
    std::string c;
public:
    FullName (std::string, std::string, std::string);
    std::string All(){return a + b + c;}
};

FullName::FullName(std::string x, std::string y, std::string z)
{
    a = x;
    b = y;
    c = z;
}

int main()
{
    FullName FNVar("My","Full","Nane");
    std::cout << FNVar.All();
}

[coder777]

the function on line 14 is called constructor. You call the constructor only when the object is constructed (on line 23)

[Pebble]

Thank's coder777.