Is a for loop like this considered bad practice? [closed]

Question

So for this example, say I have a std::vector called original and I want to split it in half into two different vectors. Assume original has an even amount of elements.

std::vector<int> firstHalf;
std::vector<int> secondHalf;

for (int i = 0, j = original.size()/2; i < original.size() / 2; i++, j++)
{
    firstHalf.push_back(original[i]);
    secondHalf.push_back(original[j]);
}

The more obvious way to do this would be to have two separate for loops, one to fill up firstHalf and one to fill up secondHalf.

Is writing the for loop like I did considered bad practice? From my testing, this solution is slightly more efficient than having two separate for loops.

Answer 1

In fact, you can reduce your code to two lines:

std::vector<int> firstHalf(original.begin(), original.begin() + original.size() / 2);
std::vector<int> secondHalf(original.begin() + original.size() / 2, original.end());

Reason:

push_back may reallocate memory while the number of elements increasing. stl would allocate enough memory once at the beginning time.