比较二维数组，然后添加它们

Question

import java.lang.Math;

public class Homework2 {
public static void main(String[] args){

    int d1 = (int) (Math.random()*(10-3+1)+3);
    int d2 = (int) (Math.random()*(10-3+1)+3);

    double[][] doubMatrix1 = new double[d1][d2];
    double[][] doubMatrix2 = new double[d1][d2];
    double[][] doubMatrix3 = new double[d1][d2];

    doubMatrix1 = getdoubMatrix(d1,d2);
    doubMatrix2 = getdoubMatrix(d1,d2);
    doubMatrix3 = addMatrices(doubMatrix1, doubMatrix2);
}
public static double[][] getdoubMatrix(int d1, int d2){

    double[][] tempArray = new double[d1][d2];

    for(int i =0; i <tempArray.length;i++ )
        for(int j =0;j < tempArray[i].length;j++)
            tempArray[i][j] = Math.random()*(10.0);

    return  tempArray;
}
public static double[][] addMatrices(double doubMatrix1[][], double doubMatrix2[][]){

    for(int i = 0; i< doubMatrix1.length;i++)
        for(int j = 0; j< doubMatrix1[i].length;j++ )
        {
            if(doubMatrix1[i][j] == doubMatrix2[i][j])
            {
                double[][] tempArray = new double[i][j];

            }
            else
            {
                return tempArray[0][0]; 
            }
        }

    return tempArray;
}
}

I'm getting error on both return statements in the addMatrices method also I don't think I'm doing it right

This is what i was supposed to do for the addMatrices method

In the addMatricesmethod,

· Check if the first dimensions and thesecond dimensions of each 2-dim. array array are the same -- if they are NOTthe same, return a 0 X 0 2-dim. array, otherwise do the following;

· Allocate memory for a local 2-dim. arraywith the same dimensions as one of the 2-dim. array parameters

· Add each corresponding element in theparameter 2-dim. arrays and store the result in the corresponding element ofthe local 2-dim. array (use nested for loops)

· Return the local 2-dim. array

Answer 1

public static double[][] addMatrices(double doubMatrix1[][], 
                                     double doubMatrix2[][]){

for(int i = 0; i< doubMatrix1.length;i++)
    for(int j = 0; j< doubMatrix1[i].length;j++ )
    {
        if(doubMatrix1[i][j] == doubMatrix2[i][j])
        {
            double[][] tempArray = new double[i][j];

        }
        else
        {
            return tempArray[0][0]; 
        }
    }

return tempArray;
}

• Well the first problem is that, in your else part you are returning a double value. ArrayElement, while the return type is defined as an array of array .

• Secondly, you have declared your tempArray inside your if and are using it outside, while returning.. It would not be visible outside your if . Declare it in your method, outside your if and for-loop.

PRIMARY MODIFICATION NEEDED : -

• Change your return statment in your else to: -

   tempArray = new double[0][0];

• And declare your tempArray outside your for-loop.

Well, there is lot more than the above problem. Your addMatrix is logically not adding your matrices. I think you should check onto that code..