Finding a vector within another vector?

[danime91]

So I'm doing this assignment for a class, and need to write a function that will basically find all elements of a vector in another vector in the same exact order, then return the starting position of the sequence. Here's what I've tried:

for (int k = 0; k != v1.size(); k++)
    {
        if (v2[0] == v1[k])
        {
            int l = k;
            int j = 0;
            while (v1[l] == v2[j])
            {
                while (l != v1.size() && j != v2.size())
                {
                    l++;
                    j++;
                }
                return k;
            }
 
        }
    }

It works fine as long as there are no repeated elements. For example, if I'm looking for a vector{1, 2, 3, 4} within vector {5, 6, 7, 1, 2, 3, 4, 2, 3}, it will come out fine, but if I try it with vector{1, 2, 3, 1, 2, 3, 4}, it fails on me.

[newb16]

It don't work at all - it return index as 'matching' element there matches first element of v2.
E.g if v2 = {1,1,2,3,4}; Hint - how many times does condition on line 7 execute?

[danime91]

Ah, actually I figured it out. Had to rewrite the two while loops and it worked fine.