Question

Sorry,

I was playing with c++ and i did something strange and it worked, someone knows why it worked.

Main.cpp

#include <iostream>
#include "c1.h"

using namespace std;

Classe c(){
    Classe v();
}
int main(){
    cout << c().x;
    return 0;
}

c1.h

#include <iostream>

using namespace std;

class Classe{

    public:
        Classe(){
            x = 100;;
    }
    int x;
    };  

So, why i can call c().x if the function Classe c(){Classe v()} dont return the variable?

No warnings with and without -wall.

if i do return v on the function it dont compile:
Error message with return:

main.cpp: In function ‘Classe c()’:
main.cpp:8: error: conversion from ‘Classe (*)()’ to non-scalar type ‘Classe’ requested

Answer 1

i think that is by accident, your compiler should have warned you that c() does not return a value.

accidentally the register used to return a value from a function happened to be loaded with the address of the local variable allocated within that function.

And, btw, your declaration of local v() in the function c() does not declare a variable of type Classe, but a function taking no arguments, returning an object of Classe.