正确的二分法数据查找算法——百度百科里的那个算法是错误的

//dichotomy algorithm
#include <iostream>

using namespace std;
const int NUM = 16;
const int Found(const int a[], const int obj, const intlen);
int main()
{
    int a[NUM]={-1,11,23,56,98,129,189,452,654,789,1023,2892,5022,6344,7680,9988};
    int isFound = NUM;
    for (int i = 0; i < NUM; i++)
    {
       cout << "a["<< i <<"]=" << a[i]<< "\t";
       if ((i+1)%3 == 0)
           cout<< '\n';
    }
    cout<< endl;
    isFound =Found(a,56,NUM);
    if (isFound == NUM)
       cout << "Data not found.\n";
    else
       cout << "Data is a[" << isFound << "]" << endl;
    return 0;
}

const int Found(const int a[], const int obj, const intlen)
{
    int front = 0, end =len-1, i=(front+end)/2;
    while ( front < end )
    {
       if (a[i] == obj)
           returni;
       else
           if (a[i] < obj)
           {
              front = i;
           }
           else
           {
              end = i;
           }
       i = (end+front)/2;
    }
    return len;
}