c++ Segmentation fault (core dumped) 的一个实例

说明：找到vector前一半元素中等于some_val的那些，然后在这些元素的前面插入它的２倍。 

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

#define LENGTH  10
typedef  int TYPE;
typedef  vector<TYPE> VECTORTYPE;

void print(VECTORTYPE & );

int main()
{
  vector<int> vint{0,1,2,3,4,5,6,6,7,7,8,8,9,10,11,12,12};
  vector<int>::iterator iter = vint.begin();
  vector<int>::iterator mid = vint.begin() + vint.size() / 2;
  int some_val = 6;
  while(iter != mid)
    {
      if(*iter == some_val)
        {
	  iter =  vint.insert(iter,2 * some_val);
          ++iter;
          ++ iter;
	  ++ mid;
	}
      else
	{
	  ++ iter;
	}
    }
  // print(vint);  
  return 0;
}
void print(VECTORTYPE &vec)
{
  for(VECTORTYPE::iterator i  = vec.begi