Binary Search in Array in C++ | HackThatCORE

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The Binary Search requires the array, to be scanned, must be sorted in any order. Binary search algorithm in C++ works only for sorted arrays and not for unsorted arrays. But Linear search array can work both for Sorted and Unsorted arrays.

Binary Search in array

#include<iostream.h>
int Bsearch(int [], int, int);        //i.e., Bsearch (the array, its size, search_item)
int main()
{
 int AR[50], ITEM, N, index;      // array can hold max. 50 elements
 cout<<"Enter desired array size (max. 50) ... ";
 cin>>N;
 cout<<"\nEnter Array elements (must be sorted in Asc order)\n";
 for(int i=0; i < N; i++)
  cin>>AR[i];
 cout<<"\nEnter Element to be searched for ... ";
 cin>>ITEM;
 index = Bsearch(AR, N, ITEM);
 if (index == -1)
  cout<<"\nSorry!! Given element could not be found.\n";
 else
  cout<<"\nElement found at index: "<<index<<", Position: "<<index+1<<endl;
 return 0;
}
int Bsearch(int AR[], int size, int item)    //function to perform binary search
{
 int beg, last, mid;
 beg=0;
 last = size - 1;
 while(beg <= last)
 {
  mid = (beg + last)/2;
  if(item == AR[mid]) return mid;
  else if (item > AR[mid]) beg = mid+1;
  else last = mid+1;
 }
 return -1;
 //the control will reach here only when item is not found
}