//文件名：CHAPTER5-11.cpp
#include <iostream>
#include <queue>
#include <assert.h>
using namespace std;
int main()
{
  queue<int> Q;
  Q.push(8);
  Q.push(7);
  Q.push(6);
  Q.push(2);
  assert(Q.size() == 4);
  assert(Q.back() == 2);
  assert(Q.front() == 8);
  cout<< Q.front();
  Q.pop();
  assert(Q.front() == 7);
  cout<< Q.front();
  Q.pop();
  assert(Q.front() == 6);
  cout<< Q.front();
  Q.pop();
  assert(Q.front() == 2);
  cout<< Q.front();
  Q.pop();
  assert(Q.empty());
  return 0;
}