Which of the following statements produces the same results as the statement: std::copy(v1.begin(), v1.end(), v2.begin());
If v1 and v2 are both 10-element vectors?
A) std::copy_backward(v1.begin(), v1.end(), v2.begin());
B) std::copy_backward(v2.begin(), v2.end(), v1.begin());
C) std::copy_backward(v1.begin(), v1.end(), v2.end());
D) std::copy_backward(v2.begin(), v2.end(), v1.end());

Question

Quizplus · Accepted Answer

The statement std::copy_backward(v1.begin(), v1.end(), v2.end()); produces the same results as the statement std::copy(v1.begin(), v1.end(), v2.begin());. The difference is that std::copy_backward copies the range from right to left, whereas std::copy copies it from left to right. However, since both vectors have the same size, the effect is the same. Option A would reverse the order of the elements, since it copies v1 elements into v2 in reverse order. Option B would copy v2 elements into v1 in reverse order, effectively overwriting v1. Option D copies v2 elements into v1 in reverse order, but starting at the end of each vector, which would also result in an incorrect order of elements.

Which of the Following Statements Produces the Same Results as the Statement