Given a sorted rotated array, find an element in O(logn) time without finding the pivot element.

//============================================================================
// Name        : SortedRotatedArray.cpp
// Author      : Varun Sharma
// Version     : 1.0
// Complexity  : O(logn)
// Description : Finding Element in a sorted rotated array, without finding pivot.
//============================================================================
/*
ALGORITHM
=========
1.  Initialize start = 0, end = size-1.
2.  Repeat while start <= end
    a.  Calculate mid element =>  mid = (start+end)/2.
    b.  If arr[mid] = val then print position and return true.
    c.  Array is sorted from start to mid or from mid to end, check which one is the case.
    d.  Sorted from Mid to end: arr[mid] < arr[end].
        i. If search value lies in right sorted half : val arr[mid] && val <= arr[end] 
           then start = mid+1
        ii.Else end = mid-1 
    e.  Else Sorted from start to mid .
        i. If search value lies in left sorted half: val <arr[mid] && val>= arr[start]
           then end = mid-1
        ii.Else start = mid+1.
3.  Return false if element not found.
*/

#include <iostream>
using namespace std;

bool search(int arr[],int size,int val) {
      int start = 0;
      int end = size-1;
      int mid;
      while(start <= end) {
            mid = (start+end)/2;

            //Value at mid == search value then return found.
            if(arr[mid] == val) {
                  cout<<"nFOUND AT POSITION : "<<mid+1;
                  return true;
            }

            //If value at mid < value at end
            //i.e. Array is sorted from mid to end.
            if(arr[mid] < arr[end]) {
                  //Value lies in right sorted half of array.
                  if(val > arr[mid] && val <= arr[end])
                        start = mid+1;
                  else
                  //Value lies in left half of array.
                        end = mid-1;
            }
            //Array is sorted from start to mid.
            else {
                  //Value lies in left sorted half of array.
                  if(val < arr[mid] && val >= arr[start])
                        end = mid-1;
                  //Value lies in right sorted half.
                  else
                        start = mid+1;
            }
      }
      return false;
}

int main() {
      int arr[] = {6,7,8,9,10,11,1,2,3,4,5};
      int size = sizeof arr/sizeof arr[0];
      if(!search(arr,size,6))
            cout<<"nVALUE DOESN'T EXIST";

      int arr1[] = {6,7,8,9,10,11,12,13,14,5};
      int size1 = sizeof arr1/sizeof arr1[0];
      if(!search(arr1,size1,5))
                  cout<<"nVALUE DOESN'T EXIST";

      int arr2[] = {5,6,7,8,9,10,11,12,13,14};
      int size2 = sizeof arr2/sizeof arr2[0];
      if(!search(arr2,size2,5))
                  cout<<"nVALUE DOESN'T EXIST";

      int arr3[] = {5,6,7,8,9,10,11,12,13,14};
      int size3 = sizeof arr3/sizeof arr3[0];
      if(!search(arr3,size3,18))
                  cout<<"nVALUE DOESN'T EXIST";

      int arr4[] = {6,7,8,9,10,11,12,13,14,5};
      int size4 = sizeof arr4/sizeof arr4[0];
      if(!search(arr4,size4,1))
                  cout<<"nVALUE DOESN'T EXIST";

      return 0;
}