Send the matrix from class to another class - c++

Question

I have a class that has a matrix
class A{
private:
int matrix[10][5];
};
Also I have other class with method that get matrix and do with it
class B{
public:
void method(/*What to write here?*/){...}
};
So, help to releaze the syntax. How to take matrix from class and send it to other class?

Answer 1

Pass by reference
void method(A& a){...}
If method doesn't need to modify a then pass by const reference
void method(const A& a){...}
Based on the comments below it seems you want something like this
class A
{
public:
void set_coordinates(...) { matrix[...][...] = ...; }
private:
int matrix[10][5];
};
class B
{
public:
void method(A& a) { a.set_coordinates(...); }
};
i.e. pass the object A to method B::method but add sufficient public methods to A so that B can do the work it needs to do. This is what encapsulation is all about.

Answer 2

You can use vector<vector<int> >. That way you can pass them around. Or you can use friend classes, or use double pointers. Let me know if you want any of these I can provide examples.
Using double pointers:
#include <iostream>
using namespace std;
class A{
private:
int **matrix;
public:
A()
{
// since 2D array is array of arrays,
// double pointer is a pointer to array of pointers
// define the matrix, first make matrix point to an array of pointers
matrix = new int*[10];
// now make each element of pointer array
// which is a pointer point to actual array
for(int i=0;i<10;i++)
matrix[i] = new int[5];
// initialize like simple 2D array (another function maybe)
for(int i=0;i<10;i++)
for(int j=0;j<5;j++)
matrix[i][j] = i+j;
}
// note the return-type
int ** getMatrix()
{
return matrix;
}
};
class B{
public:
// wherever you want to access matrix, pass the double pointer
void method(int **matrix){
for(int i=0;i<10;i++)
for(int j=0;j<5;j++)
cout << matrix[i][j] << endl;
}
};
int main() {
// create objects
A a;
B b;
// pass the double pointer to B's method
b.method(a.getMatrix());
return 0;
}