1 import java.util.Scanner;
2 /**
3 * @author 冰樱梦
4 * 时间：2018年12月
5 * 题目：求矩阵中各列数字的和
6 *
7 */
8 public class Exercise08_01 {
9 public static void main(String[] args){
10 Scanner input=new Scanner(System.in);
11 double m[][]=new double[3][4];
12 System.out.println("Enter a 3-by-4 matrix row:");
13 for(int i=0;i<m.length;i++){
14 for(int j=0;j<m[i].length;j++){
15 m[i][j]=input.nextDouble();
16 }
17 }
18
19
20 // System.out.println("Enter the columnIndex");
21 // int columnIndex=input.nextInt();
22
23 int columnIndex=0;
24 System.out.println("Sum of the elements at column "+columnIndex+" is "+sumColumn(m,columnIndex));
25 columnIndex=1;
26 System.out.println("Sum of the elements at column "+columnIndex+" is "+sumColumn(m,columnIndex));
27 columnIndex=2;
28 System.out.println("Sum of the elements at column "+columnIndex+" is "+sumColumn(m,columnIndex));
29 columnIndex=3;
30 System.out.println("Sum of the elements at column "+columnIndex+" is "+sumColumn(m,columnIndex));
31 }
32 public static double sumColumn(double m[][],int columnIndex){
33 double total=0;
34 for(int i=0;i<m.length;i++){
35 total+=m[i][columnIndex];
36 }
37 return total;
38 }
39 }
