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