#include<iostream>
using namespace std;
void BinarySearch(int a[],int num,int first,int last)
{
    if(first>last)
    {
        cout<<"\nElement not found!"<<endl;
        cout<<"———————————————————————————————————————————\n";
    }
    else
    {
        int mid;
        mid=(first+last)/2;
        if(a[mid]==num)
        {
            cout<<"\nElement found at index "<<mid+1<<endl;
            cout<<"———————————————————————————————————————————\n";
        }
        else if(a[mid]>num)
        {
            BinarySearch(a,num,first,mid-1);
        }
        else
        {
            BinarySearch(a,num,mid+1,last);
        }
    }
}

int main()
{
    int n,i,j,num,end,beg,temp;
    cout<<"———————————————————————————————————————————";
    cout<<"\nImplementation of a Binary Search";
    cout<<"\n———————————————————————————————————————————";
    try
    {
        cout<<"\nHow many numbers you want to enter ";
        cin>>n;
        if(cin.fail()) throw "";
        int a[n];
        for(i=0;i<n;i++)
        {
            cout<<"Enter Number "<<i+1<<" | ";
            cin>>a[i];
        }
        for(i=0;i<n;i++)            
        {
            for(j=i+1;j<n;j++)
            {
                if(a[i]>a[j])
                {
                    temp=a[i];                     
                    a[i]=a[j];
                    a[j]=temp;
                }
            }
        }
        cout<<"\nSorted numbers ";
        for(i=0;i<n;i++)
        {
            cout<<a[i]<<" ";
        }
        beg=0;
        end=n-1;
        cout<<"\nEnter a number to be searched ";
        cin>>num;
        BinarySearch(a,num,beg,end);
    }
    catch(...)
    {
        cout<<"\nEnter the number please"<<endl;
        cout<<"———————————————————————————————————————————\n";
    }
    return(0);
}

kodingwindow@kw:~$ g++ kw.cpp
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Implementation of a Binary Search
———————————————————————————————————————————
How many numbers you want to enter 9
Enter Number 1 | 55
Enter Number 2 | -23
Enter Number 3 | -78
Enter Number 4 | 48
Enter Number 5 | 96
Enter Number 6 | 236
Enter Number 7 | 45
Enter Number 8 | 12
Enter Number 9 | -1024

Sorted numbers -1024 -78 -23 12 45 48 55 96 236 
Enter a number to be searched -23

Element found at index 3
———————————————————————————————————————————
kodingwindow@kw:~$ 

#include<iostream>
#include<algorithm>
using namespace std;
void BinarySearch(int a[],int num,int first,int last)
{
    if(first>last)
    {
        cout<<"\nElement not found!"<<endl;
        cout<<"———————————————————————————————————————————\n";
    }
    else
    {
        int mid;
        mid=(first+last)/2;
        if(a[mid]==num)
        {
            cout<<"\nElement found at index "<<mid+1<<endl;
            cout<<"———————————————————————————————————————————\n";
        }
        else if(a[mid]>num)
        {
            BinarySearch(a,num,first,mid-1);
        }
        else
        {
            BinarySearch(a,num,mid+1,last);
        }
    }
}

int main()
{
    int n,i,j,num,end,beg,temp;
    cout<<"———————————————————————————————————————————";
    cout<<"\nImplementation of a Binary Search";
    cout<<"\n———————————————————————————————————————————";
    cout<<"\nHow many numbers you want to enter ";
    cin>>n;
    int a[n];
    for(i=0;i<n;i++)
    {
        cout<<"Enter Number "<<i+1<<" | ";
        cin>>a[i];
    }
    sort(a,a+n);
  
    cout<<"\nSorted numbers ";
    for(i=0;i<n;i++)
    {
        cout<<a[i]<<" ";
    }
    beg=0;
    end=n-1;
    cout<<"\nEnter a number to be searched ";
    cin>>num;
    BinarySearch(a,num,beg,end);
    return(0);
}

kodingwindow@kw:~$ g++ kw.cpp
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Implementation of a Binary Search
———————————————————————————————————————————
How many numbers you want to enter 9
Enter Number 1 | 55
Enter Number 2 | -23
Enter Number 3 | -78
Enter Number 4 | 48
Enter Number 5 | 96
Enter Number 6 | 236
Enter Number 7 | 45
Enter Number 8 | 12
Enter Number 9 | -1024

Sorted numbers -1024 -78 -23 12 45 48 55 96 236 
Enter a number to be searched -23

Element found at index 3
———————————————————————————————————————————
kodingwindow@kw:~$