Snippet of Bubble Sort in C++

void BubbleSort(unsigned long data[], unsigned long n)
{
    unsigned long i, j;
    bool chng = true;

    for(i=0;(i<n) && (chng == true);i++)
    {
        chng = false;
        for(j=1;j<(n-i);j++)
        {
            if( data[j-1]>data[j] )
            {
               long dummy = data[j-1];  
               data[j-1] = data[j];
               data[j] = dummy;
               chng = true;
            }
        }
    }
}