Array C++ Binary Search.

This method assumes that the set of elements in a list is first arranged in ascending or descending order. The list is initially divided into two parts and the mid point is found. If the number to be searched is less than the value of the element at the mid point, it implies that the given number lies in the first part of the list, otherwise the given number lies in the second part of the list. This is illustrated as follows:

Example

The program illustrates searching a number in a given list using Binary search.

Input and Output:

#include <iostream.h>
const int n=5;
void main() {
  int i,s,m,low=0,mid,top,p;
  int a[n];
  cout<<"Enter the number of elements";
  cin>>m;
  cout<<"Enter the elements in sorted order";
  for(i=0;i<m;i++)
     cin>>a[i];
     cout<<"Enter the element to be searched ";
     cin>>s;
     top=m;
     while(low<=top) {
       mid=(low+top )/2;
       if (s==a[mid])  {
          cout<<endl;
          cout<<"Element is present in posifion "<<mid+1;
          p=1;
          break;
       }
       else
       if (s<a[mid])
         top=mid-1;
       else
         low=mid+ 1;
}
      if (p!=1)
         cout<<"Element is not present in the list";
}

Enter the number of elements 5

Enter the elements in sorted order 2 4 7 9 10

Enter the element to be searched 7

Element is present in position 3