Trie Dichotomique output erreur

private static int binarySearch(int[] array, int fromIndex, int toIndex, int key) {
    int low = fromIndex;
    int high = toIndex - 1;
    while (low <= high) {
        int mid = (low + high) / 2;
        int midVal = array[mid];
        if (midVal < key)
            low = mid + 1;
        else if (midVal > key)
            high = mid - 1;
        else
            return mid;
    }
    return -1;
}

private static int binarySearch(int[] array, int key) {
    return binarySearch(array, 0, array.length, key);
}

public static void main(String[] args) {
    int[] tab = { 1, 3, 5, 7, 9 };
    System.out.println(binarySearch(tab, 0)); // -1: before the first
    System.out.println(binarySearch(tab, 1)); //  0: the first
    System.out.println(binarySearch(tab, 4)); // -1: not in middle
    System.out.println(binarySearch(tab, 5)); //  2: in middle
    System.out.println(binarySearch(tab, 9)); //  4: the last
    System.out.println(binarySearch(tab,10)); // -1: after the last
}

import java.util.Scanner;
public class RechDicoTab1 
{
	public static void main(String[] args) 
	{
		int[]tab={4,5,6,7,8,9,10,11};
		System.out.println("Entrez élément à trouver");
		Scanner sc=new Scanner(System.in);
		int x=sc.nextInt();
		recherche(tab,x);
		int position=recherche(tab,x);
		
		if(position>0)
		{
			System.out.println("L'élément "+x+" est trouvé en position "+position);
		}
		else
		{
			System.out.println("L'élément "+x+" n'est pas trouvé");
		}
	}

	private static int recherche(int[] tab, int elt) 
	{
		int n=tab.length-1;
		int a=1;
		int b=n;
		int p=0;
		int position=-1;
		do
		  {
			p=((a+b)/2);
			if(elt==tab[p])
			{
				position=p;
			}
			else if(tab[p]<elt)
				{
					a=p+1;
				}
			else 
				{
						b=p-1;
				}
		    }while(elt!=tab[p] && (a<=b));
		return position;
	}			
}