练习4

package test4;import java.util.Scanner;public class Test4 {public static void main(String args[]){System.out.println("请输入阶数n:");Scanner reader=new Scanner(System.in);int n=reader.nextInt();//读入一个n值int num[][]=new int[n][n];System.out.println("请输入"+n+"阶方阵");int sum1=0,sum2=0,sum=0;//存两条对角线的和for(int i=0;i<n;i++){for(int j=0;j<n;j++){num[i][j]=reader.nextInt();//将scanner的成员函数nextint()的返回值付给数组num的第i个元素if(i==j)sum1=sum1+num[i][j];if(i+j==n-1)sum2=sum2+num[i][j];}sum=sum1+sum2;}System.out.println("对角线的和为"+sum);}}