Operating on a Vector passed to a function, C++

Question

I am trying to finish a program to perform the quickselect algorithm and am using vectors since the elements are randomly generated. When I run my code as it is right now I get the error:

undefined reference to quickSelect(int, std::vector<int, std::allocator<int> >*)

When I remove all "&" and "*" symbols from the vector declarations and reference, and try to print the values of my vector in my quickSelect function, I get a bunch of random values that are not accurate. When I print the values of the vector in the main function I get proper values. This leads me to believe that there is something going on when I am passing the vector to the function. How can I have the proper values pass on to the function quickSelect?

   #include <iostream>
   #include <cstdlib>
   #include <iomanip>
   #include <ctime>
   #include <vector>
   using namespace std;

   int k, l, p, i, x, j, res;
   int val;
   int Pivot1 = rand()%50;
   int Pivot2 = rand()%50;
   int quickSelect(int, vector<int>* arr);
   vector<int> arr;

int main(){
/*
   cout << "p: ";
   cin >> p;
   cout << "k: ";
   cin >> k;
   cout << "l: ";
   cin >> l;
*/

l = 50;
vector<int> arr(l);
srand(time(0));


 for (i=0; i<l; i++){
     x = (rand()%50);
     arr[i] = x;
 }

 for (i=0; i<l; i++){
    for (j=i; j<l; j++){
        if (j != i){
            if (arr[i] == arr[j]){
                val = true;
            }
        }
        if (val == true){
            arr[i] = arr[i]+1;
        }
    }
    val = false;
}

 quickSelect(2, &arr);


}


int quickSelect(int k, vector<int> &arr){
     static int counter = 0;
     counter++;
     vector<int> small;
     vector<int> large;
     int Pivot1 = arr[rand()%50];

     l = 50;
     for (i=0; i<l; i++){
         cout << &arr[i] << endl;
     }

     //    cout << arr[0] << endl;
     //    cout << arr[16] << " " << "life" << endl;

    for(int i=0; i<l; i++){
        if (arr[i] < Pivot1) {
            small.push_back(arr[i]);
        }
        if (arr[i] > Pivot1) {
            large.push_back(arr[i]);
        }
     }

     if(k <= large.size()) {
          return quickSelect(k, large);
     } else if (k > large.size() + 1){
         return quickSelect((k - large.size() - 1), small);
     } else {
    return Pivot1;
     }

     return 0;
}