Fast method to find index of number in array

#include <iostream>

using namespace std;

int main()
{
    // Search for a specific number in an array

    int array[19] = {2, 5, 3, 8, 6, 4, 7, 1, 1, 3, 4, 8, 1, 3, 4, 1, 1, 1, 1};
    //Searching for number 5;
    int search_number = 1;
    int temp;
    int length = 19;

    //First we want to sort the array through bubble-sorting
    for(int x = 0; x < length - 1; x++)
    {
        for(int y = x + 1; y < length; y++)
        {
            if(array[x] > array[y])
            {
                temp = array[x];
                array[x] = array[y];
                array[y] = temp;
            }
        }
    }

    for(int z = 0; z < length; z++)
        cout << array[z] << " ";

    //system("cls");
    cout << endl;

    //After sorting the array you can now do the method of finding the number
    int variable = (length/2);
    cout << variable << endl;
    int middle = length/2;

    while(array[variable] != search_number)
    {
        if(array[variable] > search_number)
        {
            variable = variable/2;
        }
        else
        {
            variable = (variable / 2) + middle;
        }
    }

    cout << "The program found the search_number in index " << variable << " in the array." <<
    endl;

}