JAVA经典算法(二十九)

 题目：求一个3*3矩阵对角线元素之和

package cn.ls.lanqiao;

import java.util.*;

public class Test29 {

	public static void main(String[] args) {
		double[][] a = new double[3][3];
		double sum1 = 0;
		double sum2 = 0;
		Scanner sc = new Scanner(System.in);
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				a[i][j] = sc.nextDouble();
				if (i == j) {
					sum1 += a[i][j];
				}
				if (a.length - 1 - i == j) {
					sum2 += a[i][j];
				}
			}
		}
		System.out.println("矩阵对角线之和分别是：" + sum1 + "和" + sum2);

	}
}