【C#】【平时作业】习题-3-数组

1、 设计一个数组用于存放10个整数，然后计算这十个整数之和？

private void btn1_Click(object sender, EventArgs e)
        {
            int temp = 0;
            lblResult.Text = "";//初始清空内容
            //题目：存放10个整数然后求和
            int[] a = new int[10] { 9, 8, 2, 3, 5 ,6,4,2,7,3};
            lblResult.Text += "\n a数组元素初始值：";
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

            lblResult.Text += "\n 求和结果：";
            for (int i = 0; i < a.Length; i++)
            {
                temp += a[i];
            }
            lblResult.Text += temp.ToString();
        }

2、 设计一个数组用于存放10个整数，然后计算数组中顺序为偶数的元素之和？

注意：顺序为偶数是不是下标为偶数？

private void btn2_Click(object sender, EventArgs e)
        {
            int temp = 0;
            lblResult.Text = "";//初始清空内容
            //题目：存放10个整数然后求和
            int[] a = new int[10] { 9, 8, 2, 3, 5, 6, 4, 2, 7, 3 };
            lblResult.Text += "\n a数组元素初始值：";
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

            lblResult.Text += "\n 求和结果：";
            for (int i = 0; i < a.Length; i++)
            {
                if(i%2==0) temp += a[i];
            }
            lblResult.Text += temp.ToString();
        }

3、练习使用Array常用的属性和方法，例如length 属性，Sort 、Reverse方法。对给定数组进行排序，获取元素个数等？

private void btnEnter_Click(object sender, EventArgs e)
        {
            lblResult.Text = "";//初始清空内容
            int[] a = new int[5] {9,8,2,3,5};
            lblResult.Text += "\n a数组元素初始值：";
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

            lblResult.Text += "\n a数组元素长度："+a.Length.ToString();
            Array.Sort(a);//对数组（Array）进行排序
            lblResult.Text += "\n 使用Sort进行排序："+a[0].ToString() + "," +
                           a[1].ToString() + "," +
                           a[2].ToString() + "," +
                           a[3].ToString() + "," +
                           a[4].ToString()+"\n 使用Reverse反转：";
            Array.Reverse(a);//反转排序
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

        }

4、如何实现一维数组的元素降序排列？

private void btnEnter2_Click(object sender, EventArgs e)
        {
            lblResult.Text = "";//初始清空内容
            //题目：如何实现一维数组降序排列
            int[] a = new int[5] { 9, 8, 2, 3, 5 };
            lblResult.Text += "\n a数组元素初始值：";
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

            lblResult.Text += "\n 对a进行降序排序：" ;
            Array.Sort(a);//对数组（Array）进行排序
            if(a[0]<a[a.Length-1]) Array.Reverse(a);//如果第一个值小于最后一个值，说明是升序，则反转排序
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

        }

5、定义一个4行3列二维数组，并访问其中左下角的元素？

private void btnEnter2_Click(object sender, EventArgs e)
        {
            lblResult.Text = "";//初始清空内容
            //题目：如何实现一维数组降序排列
            int[] a = new int[5] { 9, 8, 2, 3, 5 };
            lblResult.Text += "\n a数组元素初始值：";
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }

            lblResult.Text += "\n 对a进行降序排序：" ;
            Array.Sort(a);//对数组（Array）进行排序
            if(a[0]<a[a.Length-1]) Array.Reverse(a);//如果第一个值小于最后一个值，说明是升序，则反转排序
            for (int i = 0; i < a.Length; i++)
            {
                lblResult.Text += a[i].ToString() + ",";
            }
        }