Binary Search

#include<iostream>
using namespace std;
int Binary_Search (int n,int num[],int newValue);
int main()
{
    int n,i,newValue,result;
    cout << "Enter Array Size: ";
    cin >> n;
    int num[n];
    cout << "Enter Values....." <<endl;
    for(i=0; i<n; i++)
    {
        cin >> num[i];
    }
    cout << "Input a Number to search: ";
    cin >> newValue;
    result = Binary_Search(n,num,newValue);
    if(result==-5)
    {
        cout << "Not Found" <<endl;
    }
    else
    {
        cout << "Found at Index " << result;
    }
    return 0;
}

int Binary_Search (int n, int num[],int newValue)
{
    int last,first=0,mid;
    last = n-1;
    while(first <= last)
    {
        mid = (first+last)/2;
        if(num[mid] == newValue)
        {
            return mid;
        }
        else if(newValue > num[mid])
        {
            first = mid + 1;
        }
        else
        {
            last = mid - 1;
        }
    }

    return -5;

}