Question

i have a class Matrix and I use the this pointer in the application class to access the methods of the Matrix class. For some reason it doesn’t identify the methods. This is a code snippet and it gives me an error starting with the AddMatrix method when I use

import java.io.*;
import java.util.*;
import java.util.Scanner;

class Matrix {
double [][] element;
int rows, cols ;

Matrix(int rows, int cols){
this.rows = rows;
this.cols = cols;
element = new double [rows][cols];
}

public double getValue (int row, int col){
return element[row][col];
}

public void setValue (int row, int col, double value){
element[row][col] = value;  
}

public int getNoRows(){  // returns the total number of rows
return rows;
}

public int getNoCols(){ // returns the total number of cols
return cols;
}

 // The methods for the main calculations

public Matrix AddMatrix(Matrix m2){
int row1 = getNoRows();
int col1 = getNoCols();
Matrix result = new Matrix(row1, col1);

 for (int i=0; i<row1; i++){
   for (int j=0; j<col1; j++) {
      result.setValue(i,j, (getValue(i,j) + m2.getValue(i,j)));
    }
 }
return result;
}

 public Matrix  MultiplyMatrix(Matrix m2){
   if (this.getNoCols != m2.getNoRows)
   throw new IllegalArgumentException ("matrices can't be multiplied");
   int row2 = this.getNoRows();
   int col2 = m2.getNoCols();
   Matrix result = new Matrix(row2, col2);
   for (int i=0; i<row2; i++){
   for (int j=0; j<col2; j++){
         result.setValue(i,j,(this.getValue(i,j)*m2.getValue(i,j)));
      }
  }
 return result;

 }

Answer 1

this.getNoCols != m2.getNoRows
should be
this.getNoCols() != m2.getNoRows()

You are using the syntax to access a variable instead of the syntax for calling a method.