怎么判断 b 数组的 'w'为 a 数组的第 5 项而不是第 2 项

            char[] a = new char[] { 'q', 'w', 'e', 'r','w', '1', '2' };
            char[] b = new char[] { 'w','1', '2' };
            int []c=new int[5];
            int k=0;
            for (int i = 0; i < a.Length; i++)
            {
                for (int j = 0; j < b.Length; j++)
                {
                    if (a[i] == b[j]&&a[i+1]==b[j+1])这里会报错
                    {
                        c[k] = i;
                        k++;
                        break;
                    }
                }
            }
            label1.Text = c[0].ToString();