For loop control variable name conflicts ?

[oseri]

I've got a function that has a parameter with the same name as a for loop control variable :

 void fun(const int& i = 0)
{
	std::cout << "&i: " << &i << "\n";
		for (int i = 0; i < 3; i++)
		{std::cout << "loop &i: " << &i << "\n";}
	std::cout << "&i: " << &i << "\n";
}

int main()
{
	fun(1);
	return 0;
}

I'd half expected that complier will yell at me for redefining the i variable but it compiles and runs just fine. Both i variables have different addresses.

I know that it's probably a bad design, even if its a defined behaviour (is it ?). Is there any way to access the "outside" i variable inside the for loop ?

[TarikNeaj]

The reason it works in your code, is becuase you created the other variable inside the for-loop. So it is only defined inside the for-loop.

for (int i = 0; i < 3; i++)
{std::cout << "loop &i: " << &i << "\n";} // Its recognized here.
// Not recognized it. It goes out of scope one the for-loop is done.  

Edit: Another example.

if(something)
{
   int x = 5; // create variable
   x = 10; // change its value, works fine
}

x = 15; // Does not work, becuase x was created inside the if statement, and does not exist outside of that. 

[dhayden]

It's legal. When multiple instances of a name are in scope, the inner-most scope is the one that wins.