Question

我写了这个程序来添加两个3x3矩阵;谁能告诉我为什么我的输出会产生2个结果矩阵???

package programExam;
import java.io.*;
import java.util.*;
import java.io.File.*;
import java.util.Scanner;

public class progEx {
    public static void main(String[]args){
        Scanner input = new Scanner(System.in);

        int N = 3;

        //get the users input and store it in the two arrays
        System.out.println("\nEnter matrix1: \n");

        //declare 2 array with the appropriate number of rows
        //and columns in them to store the numbers in each matrix.
        //this is the first one.
        double[][]matrix1 = new double[N][N];

        for (int i = 0; i< matrix1.length; i++){
            for (int j = 0; j< matrix1[i].length; j++){
                matrix1[i][j] = input.nextDouble();
            }
        }

        //get the users input and store it in the two arrays
        System.out.println("\nEnter matrix2: \n");


        double [][] matrix2 = new double [3][3];

        for (int i = 0; i< matrix1.length; i++){
            for (int j = 0; j< matrix1[i].length; j++){
                matrix2[i][j]= input.nextDouble();
            }


        }
        //call the addMatrix method and pass it the two arrays
        System.out.println("The addition of the matrices is: ");

        double[][] resultingMatrix = addMatrix(matrix1, matrix2);



    }//end of main method


    //write the addMatrix method to add the two matrices and display the result

    public static double[][] addMatrix(double[][] m1, double[][] m2){

        double[][] result = new double[m1.length][m1[0].length];

        for (int i = 0; i < result.length; i++) {
            for (int j = 0; j < result[0].length; j++){
                result[i][j]= m1[i][j] += m2[i][j];
            }
        }

        for (int i = 0; i < m1.length; i++) {
            for (int j = 0; j < m1[0].length; j++) {
             System.out.print("  " + m1[i][j]);
            }

            for (int j = 0; j < result[0].length; j++) {
                System.out.print("  " + result[i][j]);
            }
            System.out.println();
        }
    return result;
    }//end of add matrices

    //end of class  
    }

输出：

Enter matrix1: 

4 5 1 
4 3 2
6 3 9

Enter matrix2: 

9 2 4
7 4 2 
1 7 5

The addition of the matrices is: 

13.0  7.0  5.0  13.0  7.0  5.0
11.0  7.0  4.0  11.0  7.0  4.0
7.0  10.0  14.0  7.0  10.0  14.0

Answer 1

因为System.out.print函数中有两个addMatrix()命令。

我相信这段代码：

    for (int i = 0; i < m1.length; i++) {
        for (int j = 0; j < m1[0].length; j++) {
         System.out.print("  " + m1[i][j]);
        }

        for (int j = 0; j < result[0].length; j++) {
            System.out.print("  " + result[i][j]);
        }
        System.out.println();
    }

应该简单地说：

    for (int i = 0; i < result.length; i++) {
        for (int j = 0; j < result[0].length; j++) {
            System.out.print("  " + result[i][j]);
        }
        System.out.println();
    }

另外，请注意您正在修改同一功能中的矩阵m1（不经意间，我相信）。在我看来这一行：

result[i][j]= m1[i][j] += m2[i][j];

应该是

result[i][j]= m1[i][j] + m2[i][j];

（请注意+=已替换为+）

输出将无法正确显示所得矩阵

1 个答案: