Exercise_1.cpp

//time complexity for nlogn 
// it is in space no extra memory
#include <stdio.h> 
  
// A recursive binary search function. It returns 
// location of x in given array arr[l..r] is present, 
// otherwise -1 
int binarySearch(int arr[], int l, int r, int x) 
{   
    //Your Code here 
    while(l<=r){
    	int mid = (l+r)/2;
    	
    	if(arr[mid] == x){
    		return mid;
    	} else if (arr[mid]> x)  {
    		r = mid -1;
    	} else {
    		l = mid +1;
    	}
    }
    
    return -1;
} 
  
int main(void) 
{ 
    int arr[] = { 2, 3, 4, 10, 40 }; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    int x = 10; 
    int result = binarySearch(arr, 0, n - 1, x); 
    (result == -1) ? printf("Element is not present in array") 
                   : printf("Element is present at index %d", 
                            result); 
    return 0; 
}