Binary Search | C ++ program to implement recursive Binary Search ; A recursive binary search function . It returns location of x in given array arr [ l . . r ] is present , otherwise - 1 ; If the element is present at the middle itself ; If element is smaller than mid , then it can only be present in left subarray ; Else the element can only be present in right subarray ; We reach here when element is not present in array ; Driver method to test above
#include <bits/stdc++.h> NEW_LINE using namespace std ; int binarySearch ( int arr [ ] , int l , int r , int x ) { if ( r >= l ) { int mid = l + ( r - l ) / 2 ; if ( arr [ mid ] == x ) return mid ; if ( arr [ mid ] > x ) return binarySearch ( arr , l , mid - 1 , x ) ; return binarySearch ( arr , mid + 1 , r , x ) ; } return -1 ; } int main ( void ) { int arr [ ] = { 2 , 3 , 4 , 10 , 40 } ; int x = 10 ; int n = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ; int result = binarySearch ( arr , 0 , n - 1 , x ) ; ( result == -1 ) ? cout << " Element ▁ is ▁ not ▁ present ▁ in ▁ array " : cout << " Element ▁ is ▁ present ▁ at ▁ index ▁ " << result ; return 0 ; }