二分查找

#include <iostream>
#include <cstdlib>
using namespace std;

int binSearch(const int a[], int beg, int end, int value)
{
    while(beg <= end)
    {
        int mid = beg + (end - beg) / 2;
        if(a[mid] == value)
            return mid;
        else if(a[mid] < value)
            beg = mid + 1;
        else
            end = mid - 1;
    }
    return -1;
}

int main(int argc, char **argv)
{
    int a[] = {1, 3, 5, 7, 8};
    int value = atoi(argv[1]);
    size_t size = sizeof(a) / sizeof(int);
    int loc = binSearch(a, 0, size-1, value);
    if (loc == -1)
        cout << "Not find" << endl;
    else 
        cout << "Loc:" << loc << endl;
}