Concatenating two std::vectors

Question

How do I concatenate two std::vectors?

Answer 1

You can prepare your own template for + operator:

template  
inline T operator+(const T & a, const T & b)
{
    T res = a;
    res.insert(res.end(), b.begin(), b.end());
    return res;
}

Next thing - just use +:

vector a{1, 2, 3, 4};
vector b{5, 6, 7, 8};
for (auto x: a + b)
    cout << x << " ";
cout << endl;

This example gives output:

1 2 3 4 5 6 7 8