6.binary_search查找

#include<iostream>
#include<Windows.h>
using namespace std;

#include<vector>
#include<algorithm>

//二分查找法(必须在有序的序列中查找)
//bool binary_search(iterator begin, iterator end, value);
//查找指定的元素value，找到返回true，否则返回false

void test0601()
{
    vector<int> v;

    for (int i = 0; i < 10; i++)
    {
        v.push_back(i);
    }
    //v.push_back(2);如果是无序序列，查找结果未知
    
    double t0 = GetTickCount()/1000.0;//测量不出来，无法精确到us
    int ret=binary_search(v.begin(), v.end(), 9);
    double t1 = GetTickCount()/1000.0 - t0;
    if (ret)
    {
        cout << "找到了" <<"用了"<< t1 << endl;
    }
    else
    {
        cout << "未找到" << endl;
    }
    

    //对比二分法查找和普通查找的速度
    t0 = GetCurrentTime() / 1000.0;
    vector<int>::iterator it=find(v.begin(), v.end(), 5);
    t1 = GetTickCount()/1000.0 - t0;

    if (it == v.end())
    {
        cout << "未找到" << endl;
    }
    else
    {
        cout << "找到了" << "用了" << t1 << endl;
    }
}
int main()
{
    test0601();

    system("pause");
    return 0;
}