import java.util.Scanner;

 /**

  * @author 冰樱梦

  * 时间：2018年12月

  * 题目：求矩阵主对角线元素的和

  *

  */

 public class Exercise08_02 {

     public static void main(String[] args){

         Scanner input=new Scanner(System.in);

         System.out.println("Enter the arrays row: ");

         int row=input.nextInt();

         System.out.println("Enter the arrays column: ");

         int col=input.nextInt();

         double[][] list=new double[row][col];

         for(int i=0;i<list.length;i++){

             for(int j=0;j<list[i].length;j++){

                 list[i][j]=input.nextDouble();

             }

         }

         System.out.println("Sum of the elements in the major diagonal is "+sumMajorDiagonal(list));

     }

     /**

      * @param m

      * @return

      * 返回主对角线的和

      */

     public static double sumMajorDiagonal(double [][] m){

         double total=0;

         for(int i=0;i<m.length;i++){

             total+=m[i][i];

         }

         return total;

     }

 }