泛型算法之二分查找实现，及简单测试。查找范围可以是C++内置指针或者容器的迭代器，查找内容可以是char,int等类型

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

template <typename Randomaccessiterator, typename T>
Randomaccessiterator BinarySearch(Randomaccessiterator begin, Randomaccessiterator end, T key)
{
    auto cpy_end = end;
    end--;
    int len;
    auto mid = begin;
    while (begin <= end)
    {
        len = end - begin;
        mid = len / 2 + begin;
        if (key< *mid)
            end = mid - 1;
        else if (key>*mid)
            begin = mid + 1;
        else
            return mid;
    }
    return cpy_end;

}

int a[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
int main()
{
    cout << *BinarySearch(a, a + 10, 3)<<endl;

    vector<char> cvec;
    for (int i = 0; i < 10; ++i)
        cvec.push_back('a' + i);

    auto result = BinarySearch(cvec.begin(), cvec.end(), 'c');
    if (result != cvec.end())
        cout << *result << endl;

    result = BinarySearch(cvec.begin(), cvec.end(), 'v');
    if (result != cvec.end())
        cout << *result << endl;
    else
        cout << "not find" << endl;
}

测试结果