java经典算法_026求一个3*3矩阵对角线元素之和

package wzs.arithmetics;

// 题目：求一个3*3矩阵对角线元素之和
public class Test_wzs26
{
    public static void main(String[] args)
    {
        int array[][] =
        {
                {
                        1, 2, 3
                },
                {
                        4, 5, 6
                },
                {
                        7, 8, 9
                }
        };

        System.out.println("打印矩阵:");
        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                System.out.print(array[i][j] + "\t");
            }
            System.out.println();
        }
        System.out.println("打印出对角元素,并求和.");
        int sum = 0;
        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                if (i == j)
                {
                    sum += array[i][j];
                    System.out.print(array[i][j] + "\t");
                }
            }
        }
        System.out.println("对角元素和:" + sum);

        int sum2 = 0;
        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                if (i + j == 2)
                {
                    sum2 += array[i][j];
                    System.out.print(array[i][j] + "\t");
                }
            }
        }
        System.out.println("对角元素和:" + sum2);
    }
}

输出结果:

打印矩阵:
123
456
789
打印出对角元素,并求和.
159对角元素和:15
357对角元素和:15