本人菜鸟，利用 for 语句给数组赋值并用 for 语句输出，源程序如下，哪里出错了呢

private void button2_Click(object sender, EventArgs e)
        {
           
            for (int i = 0; i < 6; i++)
            {
                a[i] = Convert.ToInt32(p.Text);
            }
        }
 private void button1_Click(object sender, EventArgs e)
        {
            int j = 0;
            for (j = 0; j < 6; j++)
            {
                label1.Text += (a[j]);
            
            
            }
        }