Russian Qt Forum

C++ (Qt)
void traverse(vector<int> v, bool reverse)
{
    auto it  = reverse ? v.crbegin() : v.cbegin();
    auto end = reverse ? v.crend()   : v.cend();
    while (it != end)
    {
        auto n = *it++;
        ...
    }
}

C++ (Qt)
void traverse(vector<int> v, bool reverse)
{
    auto vv = v;
    if (reverse)
        std::reverse(vv.cbegin(), vv.cend());
    for (auto n : vv)
    {
        ...
    }
}

C++ (Qt)
for (size_t i = 0; i < vec.size(); ++i) {
 size_t index = reverse ? (vec.size() - i - 1) : i;
 vec[index] = ...
}
 

C++ (Qt)
auto itF = vec.begin();
auto itB = vec.rbegin();
 
whle (true) {
  if (!reverse && itF == vec.end()) break;
  if (reverse && itB == vec.rend()) break;
  auto & val = reverse ? (*itB++) : (*itF++);
  ...
}
 

C++ (Qt)
template<typename Container, typename Func>
void func( Container c, Func func, bool reverse )
{
	if( reverse )
		for_each( c.crbegin(), c.crend(), func );
	else
		for_each( c.cbegin(), c.cend(), func );
}
 
int main( int, char *[] )
{
	vector<int> data { 10, 20, 30, 40, 50 };
 
	func( data, [=]( int v ){ cerr << v << endl; }, false );
 
	return 0;
}
 

C++ (Qt)
auto itF = vec.begin();
auto itB = vec.rbegin();
 
whle (true) {
  if (!reverse && itF == vec.end()) break;
  if (reverse && itB == vec.rend()) break;
  auto & val = reverse ? (*itB++) : (*itF++);
  ...
}