Strange use of pointers and functions = SO confused!

[adem]

Hi, I was shown this code by a friend and (though I'm not entirely that experienced with c++) I had never seen or known anything such as function()=6 to be possible. Especially in this context!

I've searched google but to no avail, is this a documented technique or is it just a funny result of dodgy programming and memory allocation?

Here's the code:

#include <iostream>
using namespace std;

int gg=0;
int gb=10;
int h = 0;
int& function()
{
return gg;
}

int main() {
cout<<gg;
function()=6;
cout<<gg;
return 0;
}

I compiled this with g++ and the result from running is 06, by looking at the code I assumed it wouldn't have even compiled and even by some magic it did I assumed the result would be 00!

If you replace "return gg;" with say "return h;" you'll get 0. So why and how is function() tied to the variable gg?

Any help from someone better than me would be great! Thanks!
Adem

[z05DSL3A]

function() returns a reference to gg, so when function()=6 gets evaluated, the reference to gg gets resolved and then 6 is assigned to that reference thus gg becomes 6.

[adem]

I see, I assumed it was referencing but what I don't understand is how "int& function()" references gg? How would I make it reference say h?

Thankyou by the way!

[helios]

gg is a global variable.
function() return a reference (which is sort of an alias) to gg.
Therefore, function()=6; can be replaced by gg=6;.

[adem]

Never mind, I realised my own stupidity and now the code makes sense. HA.

Effectively whilst playing around with it I was changing "return gg;" to "return h;" but making the epic error of not replacing gg with h in the cout lines. Now it makes so much more sense lol.

Thanks very much again!
Adem

[Disch]

When you call function, conceptually, the function name is "replaced" with the return value.

int gg=0;

int& function()   // this function returns a reference
{
  return gg;   // returns a reference to 'gg'
}

int main()
{
  // this line:
  function()=6;

  // is functionally equivilent to this:
  int& reference_to_gg = function();
  reference_to_gg = 6;

If you want to refer to another variable, simply have 'funciton' return something else. Whatever it returns is what gets referred to.

edit -- blah I'm too slow XD