JAVA 基础编程练习题29 程序 29 求矩阵对角线之和

Posted 2022-08-27 denggelin

 

29 【程序 29 求矩阵对角线之和】

题目：求一个 3*3 矩阵对角线元素之和

程序分析：利用双重 for 循环控制输入二维数组，再将 a[i][i]累加后输出。

 

package cskaoyan;

public class cskaoyan29 
	@org.junit.Test
	public void diagonal() 
		java.util.Scanner in = new java.util.Scanner(System.in);
		int[][] arr = new int[3][3];

		for (int i = 0; i < arr.length; i++) 
			for (int j = 0; j < arr[i].length; j++) 
				arr[i][j] = in.nextInt();
			
		

		sum(arr);
		in.close();
	

	private void sum(int[][] arr) 
		int sum1 = 0;
		int sum2 = 0;

		for (int i = 0; i < arr.length; i++) 
			for (int j = 0; j < arr[i].length; j++) 
				if (i == j) 
					sum1 += arr[i][j];
				

				if (j == arr[i].length - i - 1) 
					sum2 += arr[i][j];
				
			
		

		System.out.println("主对角线元素之和:" + sum1);
		System.out.println("副对角线元素之和:" + sum2);