Cautare binara

int CautBin(int st, int dr, int x)
{
    while(st <= dr)
    {
        m = (st + dr) / 2;
        if(a[m] == x) return m;
        else if(a[m] < x) st = m + 1;
        else dr = m - 1;
    }
    return -1;
}