Concatenating two std::vectors

Question

How do I concatenate two std::vectors?

Answer 1

To be honest, you could fast concatenate two vectors by copy elements from two vectors into the other one or just only append one of two vectors!. It depends on your aim.

Method 1: Assign new vector with its size is the sum of two original vectors' size.

vector concat_vector = vector();
concat_vector.setcapacity(vector_A.size() + vector_B.size());
// Loop for copy elements in two vectors into concat_vector

Method 2: Append vector A by adding/inserting elements of vector B.

// Loop for insert elements of vector_B into vector_A with insert() 
function: vector_A.insert(vector_A .end(), vector_B.cbegin(), vector_B.cend());