Nested for loop to assign the elements of the parameter to the corresponding elements of the field-CodePudding

I'm very new to writing java code and could really use some help! I am doing a project where I'm stuck on how to write one of the methods...The setMatrixVals(mVals) setter method must make a copy of the parameter and the copy becomes a private field. I've been told to set up nested for loop and assign the elements of the mVals parameter to the corresponding elements of the matrixVals field (which is a 2D int array). And I'm very stuck on how to write it...

Here is some of my code before this method if that helps at all:

//make public class
public class Matrix
{
   //field for two dim arrays
   private int [][] matrixVals;

   //constructor
   public Matrix (int mVals[][])
   {
      //call the setMatrixVals( ) method to assign the correct information to the 
private field
      setMatrixVals(mVals);
   }

   //setter method
   public void setMatrixVals (int [][] mVals)
   {
      matrixVals = new int[mVals.length][mVals[0].length];
  
      //set up nested for loop and assign the elements of the mVals parameter to the 
     //coressonding elements of the matrixVals feild

   }

Thank you in advance!

CodePudding user response：

Here is your setMatrixVals method. Its pretty simple

public void setMatrixVals(int[][] mVals)
{
  int rows = mVals.length;
  int cols = mVals[0].length;
  matrixVals = new int[rows][cols];
  
  for(int i=0;i<rows;i  ){
    for(int j=0;j<cols;j  ){
      matrixVals[i][j] = mVals[i][j];
    }
  }

}

CodePudding user response：

Since array is Object in java you could use clone() method:

public void setMatrixVals (int [][] mVals)
{
    matrixVals = new int[mVals.length][];
    for (int i = 0; i < mVals.length; i  ) {
        matrixVals[i] = mVals[i].clone();
    }
}

CodePudding user response：

Here is a sample application, based on your code, that will hopefully help you to get acquainted with multidimensional arrays and for loops

public class Matrix {

    protected int[][] matrixVals;

    public Matrix (int matrixVals[][]) {
        setMatrixVals(matrixVals);
    }

    public void setMatrixVals (int[][] matrixVals) {
        this.matrixVals = new int[matrixVals.length][matrixVals[0].length];
        for (int a = 0; a < matrixVals.length; a  ) {
            for (int b = 0; b < matrixVals[0].length; b  ) {
                this.matrixVals[a][b] = matrixVals[a][b];
            }
        }
    }

    public int[][] getMatrixVals() {
        return matrixVals;
    }

    public static void main(String[] args) {

        int[][] matrixVals = {{1, 2, 3}, {4, 5, 6}};

        Matrix matrix = new Matrix(matrixVals);

        int[][] result = matrix.getMatrixVals();

        for (int a = 0; a < result.length; a  ) {
            for (int b = 0; b < result[0].length; b  ) {
                System.out.println(result[a][b]);
            }
        }

    }

}

Fabio