C ++ binary search algorithm

#include <iostream>
 using  namespace std; 

// Binary search method, find the elements of an array, and return the index of the position,
 // must be an ordered array, 
int select_arr ( int arr [], int len , int arr_value) 
{ 
    while ( 1 ) 
    { 
        int left = 0 ;   // left subscript of the array 
        int right = len- 1 ; // right subscript of the array 
        while (left <= right)   
        { 
            int mid = ( left + right) / 2 ;   // define the middle index
            int mid_value = arr [mid];   // define the reference value of the intermediate value 
            if (mid_value == arr_value)   // if the reference value is exactly equal to the value to be found, then automatically return to the location you want 
            {
                 return mid; 
            } 
            // if The reference value is greater than the value to be searched, indicating that the value is on the left half, and the new search range is the middle value -1 digits, which is mid-1 
            else  if (mid_value> arr_value) 
            { 
                right = mid- 1 ; 
            } 
            // if the reference value Less than the value to be searched, indicating that the value is on the right half, the new search range is the middle number +1 digits, which is mid + 1; 
            else  if (mid_value < arr_value) 
            { 
                left = mid + 1; 
            } 
        } 
        return - 1 ; 
    } 
} 


int main () 
{ 
    // define an int array and use binary search for 
    int arr [ 10 ] = { 1 , 3 , 5 , 7 , 9 , 10 , 16 , 46 , 88 , 91 }; 
    
    int weizhi = select_arr (arr, 10 , 16 ); 


    return  0 ; 
}