copy part of vector 1 to vector 2

[mce]

Hi,

I am trying to copy vector to vector as follow:

std::vector<unsigned char> vec1;

//insert some values into vec1

std::vector<unsigned char> vec2;


//now i wanto to copy 2 bytes from vec1 starting at index 5., why do i need to know how many bytes from the end of vec1?? can't i just specify how many bytes i want to copy from starting index?

std::copy(vec1.begin()+5, vec1.end()-??, vec2.begin());