iterator

int d1[4] = {1,2,3,4};
int d2[4] = {5,6,7,8};
vector v1(d1,d1 + 4), v2(d2,d2 + 4), v3(d2,d2 + 4), v4;

copy(v1.begin(),v1.end(),v2.begin());           // copy - .begin()
copy_backward(v1.begin(),v1.end(),v3.end());    // backward - .end()
copy(v1.begin(),v1.end(),back_inserter(v4));    // init a empty vector