Matrix.cpp
 
//#include <iostream>
//#include <vector>
//using namespace std;
 
Matrix::Matrix (int n, int m) {
  Ni = n;
  Nj = m;
}
 
Matrix::fill() {
  for (int i=0; i<Ni; i++) {
    for (int j=0; j<Nj; j++) {
      M[i][j] = rand();
    }
  }
}
 
 
 
Matrix.h
 
 
#include <iostream>
#include <vector>
#include <cstdlib> 
 
#ifndef MATRIX_H
#define MATRIX_H
 
using namespace std;
 
class Matrix {
 private: 
  vector < vector<float> > M;
  int Ni, Nj;
 public:
  Matrix () {};
  Matrix (int, int);
  void fill();
};
 
#endif
 
 
TestMatrix.cpp
 
#include "Matrix.h" 
 
int main() {
  cout << "hi" << endl;
  Matrix M (3, 1);
  //M.fill();
  return 0;
}