std vector与std list的效率比较

一直想知道std中vector和list的效率哪个高些。

于是做了一个简单的测试，对std vector和list的push_back与遍历操作的效率进行比较。

结果如下：

1. push_back操作：连续push_back操作100000个元素，然后clear()。一直重复10000次。

vector耗时13s, list耗时118s

2. 遍历操作：采用迭代器对100000个元素的vector和list遍历，遍历10000次。
vector耗时20s, list耗时15s


可见，如果是有序的添加元素，vector比list的效率要高将近10倍，而采用迭代器遍历元素时则效率相差不大。

附代码：

 #include
 #include
 #include
 #include

 using namespace std;

 class Message
 {
 };

 int main()
 {
     vector vt;
     list lt;

     Message *msg = new Message();
     time_t start = time(NULL);
     for (int i = 0; i < 10000; ++i) {
         vt.clear();
         for (int j = 0; j < 100000; ++j) {
             vt.push_back(msg);
         }
     }

     time_t end = time(NULL);
     cout << "vector spend time " << end - start << endl;

     start = time(NULL);
     for (int i = 0; i < 10000; ++i) {
         lt.clear();
         for (int j = 0; j < 100000; ++j) {
             lt.push_back(msg);
         }
     }

     end = time(NULL);
     cout << "list spend time " << end - start << endl;
     delete msg;
     msg = NULL;

     start = time(NULL);
     for (int i = 0; i < 10000; ++i) {
         typeof(vt.begin()) it = vt.begin();
         while (it != vt.end()) {
             msg = *it;
             ++it;
         }
     }

     end = time(NULL);
     cout << "vector spend time " << end - start << endl;

     start = time(NULL);
     for (int i = 0; i < 10000; ++i) {
         typeof(lt.begin()) it = lt.begin();
         while (it != lt.end()) {
             msg = *it;
             ++it;
         }
     }

     end = time(NULL);
     cout << "list spend time " << end - start << endl;

     return 0;
 }

输出：

vector spend time 13
list spend time 118
vector spend time 20
list spend time 15