Self implementation of std::next_permutation(), just want to check something

[georgep]

I wrote my own version of next_permutation() and it works fine, but am I missing something?

bool next_permutation(vector<int>& vec)
{ 
  for(vector<int>::iterator it = vec.end(); it != vec.begin(); it--)
  {
  
    if(*(it - 1) < *(it))
    { 
      for(vector<int>::iterator min = vec.end(); min != it-1; min--)
      {
        if(*min > *(it - 1))
        {
          swap(*(it-1), *min);
          break;
        }
      }
        
      reverse(it, vec.end());
      
      return true;
    }   
    
  }
  
  return false;
}

The output works fine when using this loop:

  do
  {
    for(vector<int>::iterator it = vec.begin(); it != vec.end(); it++)
      cout << *it << " ";
    
    cout << endl;
  
  } while(next_permutation(vec));

even when I comment out the return false; line, which makes me think the compiler is adding something.

The idea is that the function should return false if the given string/vector is already the last permutation, but true if a new one is generated.

What I have seems fine to me, but the fact that it still works with a crucial line removed worries me. Is it just the compiler adding return false at the end of the function for me that is creating this result?

Thanks!

[soranz]

Doesn't the compiler warn that not all control statements return a value ? Just set a breakpoint on return false; to test that your code reaches that line when it's supposed to.

[georgep]

Nope, no complaints from the compiler.

Instead of setting a breakpoint (because I don't know how) I just added an output line and got the expected result, thanks for the help.