Segmentation fault: vector to function

Can some one please tell me why I'm getting a 'Segmentation fault' on this code?

Code:

#include <iostream>
#include <vector>
#include <queue>
using namespace std;

int radixSort(vector<long> &, int);

int main(){

  vector<long> to_Sort;
  long int_Read = 0;

  while(cin >> int_Read){
    cin >> int_Read;
    to_Sort.insert(to_Sort.begin(), int_Read);
  }

  cout << to_Sort.size() << " ";

  radixSort( to_Sort, to_Sort.size() );

  cout << to_Sort[0] << endl;


  return 0;

}

int radixSort( vector<long> & to_Sort, int list_Size ){

  int i, j, k, cur_Factor;
  const int max_Digits = 10;

  queue<long> pass_Qu[max_Digits];
  for( i = 0, cur_Factor = 1; i < max_Digits; cur_Factor *= max_Digits, i++ ){
    for( j = 0; j < list_Size; j++ ){
      pass_Qu[( to_Sort[j] / cur_Factor ) % max_Digits].push( to_Sort[j] );
  
    }
    for( j = k = 0; j < max_Digits; j++ ){
      while( !pass_Qu[j].empty() ){
         to_Sort[k++] = pass_Qu[j].front();
      }
    }


  }
  return 0;
}

Thank you.

Not the segfault, but there's an error here:

Code:

  while(cin >> int_Read){
    cin >> int_Read;

The second read is incorrect. Remove it.

The segfault is because front() doesn't remove the element from a queue, so the refill loop goes on forever, overflowing to_Sort. You need to call pop() in the loop.