Java开发练习1 求一个n阶方阵对角线元素之和。

求一个n阶方阵对角线元素之和。

import java.util.*;public class Fangzhen {public static void main(String[] args) {// TODO Auto-generated method stubint n = 0;Scanner num = new Scanner(System.in);System.out.println("请输入阶数："); n = num.nextInt();int[][] a =new int[n][n];Scanner reader = new Scanner(System.in);System.out.println("请输入元素：");for(int i = 0;i<n;i++){for(int j = 0;j<n;j++){a[i][j] = reader.nextInt();}}int nm1,nm2,sum1 = 0,sum2 = 0,sum=0;for(int i = 0;i<n;i++){nm1 = a[i][i];sum1 = sum1 + nm1;}for(int i = 0,j=n-1;i<n;i++,j--){nm2 = a[i][j];sum2 = sum2+nm2;}sum = sum1+sum2;System.out.println("对角线上元素之和是"+sum);}

}