[Java知识库]黑皮书编程练习题8.2

import java.util.Scanner;

public class Exercise08_02 {
    public static void main(String[] args) {
        double[][] array=new double[4][4];
        Scanner input=new Scanner(System.in);
        System.out.println("Enter a 4-by-4 matrix row by row");
        for (int row=0;row<array.length;row++){
            for (int column=0;column<array[row].length;column++){
                array[row][column]=input.nextDouble();
                System.out.print(array[row][column]+" ");
            }
            System.out.println();
        }
        System.out.println("Sum of the elements in the major daigonal is "+sumMajorDiagonal(array) );

    }
    public static double sumMajorDiagonal(double[][] m){
        double total=0;
        for (int row=0,column=0;row<m.length;row++,column++){   //取主线上的值
            total+=m[row][column];  //求和
        }
        return total;
    }
}