Creating a new object seems change another object previously created (???) - c++

Question

I have a probem with a class I'm writing.
It consists in a Matrix represented as an std::array of std::array. So the first array is a sort of container of columns or rows (this can be decided by the user).
The class keeps trave of this by using a boolean.
When I create a single instance of that all seems ok, the problem appears when i create an another instance: the second instance is ok, while in the first the boolean value changes.
I can't figure out the reason of this behaviour.
The problem is present only if i put the initializeToZero() method inside the default constructor, or also with the copy constructor. Moreover the 2 instance must have the same numberOfColumn, otherwise the problem does not appear.
I link you the most relevant part of the code:
#include <stdio.h>
#include <array>
using namespace std;
template <typename scalar,int numberOfRows,int numberOfColumns> class FullArrayMatrix {
bool onlyColumnBased; //if true the first array contains the columns
array<array<scalar, numberOfRows>, numberOfColumns> verticalMatrixArray;
array<array<scalar, numberOfColumns>, numberOfRows> horizontalMatrixArray;
// if onlyColumnBased is true tre programm considers only verticalMatrixArry, if false only horizontalMatrixArray
public:
///CONSTRUCTOR
FullArrayMatrix (bool forceColumnBased=true):onlyColumnBased(forceColumnBased){
initializeToZero();
} //default initializer
bool getOnlyColumnBased() const;
void print();
///OPERATOR
scalar & operator ()(int riga, int colonna);
};
//initializeToZero
template <typename scalar,int numberOfRows,int numberOfColumns>
void FullArrayMatrix<scalar,numberOfRows,numberOfColumns>::initializeToZero() {
for (int i=1; i<=numberOfRows; i++) {
for (int j=1; j<=numberOfColumns; j++) {
if ((*this)(i,j)) {
(*this)(i,j)=0;
}
}
}
}
//print
template<typename scalar,int numberOfRows,int numberOfColumns> void FullArrayMatrix<scalar, numberOfRows, numberOfColumns >::print(){
cout<<endl<<"--"<<endl;
if (getOnlyColumnBased()) {
for (int i=1; i< numberOfRows+1; i++) {
cout<<"|\t";
for (int j=1; j< numberOfColumns+1; j++) {
cout<<(*this)(i,j)<<"\t";
}
cout<<"|"<<endl;
}
}
else {
for (int i=1; i< numberOfColumns+1; i++) {
cout<<"|\t";
for (int j=1; j< numberOfRows+1; j++) {
cout<<(*this)(i,j)<<"\t";
}
cout<<"|"<<endl;
}
}
cout<<"--"<<endl;
}
template <typename scalar,int numberOfRows, int numberOfColumns> scalar & FullArrayMatrix<scalar,numeroRighe,numeroColonne>::operator ()(int row, int column){
if (getOnlyColumnBased()) {
return verticalMatrixArray[column][row];
} else {
return horizontalMatrixArray[row][column];
}
}
This is the main:
FullArrayMatrix<double, 10, 1> full1(true);
full1.print();
cout<<full1.getOnlyColumnBased()<<endl;
FullArrayMatrix<double, 10, 1> full2(true);
cout<<endl<<endl<<full1.getOnlyColumnBased()<<full2.getOnlyColumnBased()<<endl;
full1.print();
full1.initializeToZero();
full1.print();
And this is the output:
--
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
--
1
01
--
| 0 0 0 0 0 0 0 0 0 3.49057e-320 |
--
--
| 0 0 0 0 0 0 0 0 0 0 |
--
Thank you very much for any help!

Answer 1

It seems you have an off-by-one error ("there are two hard problems in computer science: naming things, cache coherency, and off-by-one errors"): C++ uses zero based arrays. You are accessing indices 1...numberOf... in your initializeToZero() method. As a result you'll have a buffer overrun which, apparently, results in some of your variables being overwritten.

Answer 2

After the first comment I discovered a stupid error, now the only problem is in the copy constructor. As described before it seems to change onlyColumnBased in the input matrix.
How can it change this value? inputMatrix is a const reference, isn't it?
The code is the following:
In the declaration:
FullArrayMatrix (const FullArrayMatrix<scalar,numeroRighe,numeroColonne> &inputMatrix,bool forceColumnBased=true);
In the implementation:
template <typename scalar,int numberOfRows, int numberOfColumns> FullArrayMatrix<scalar, numberOfRows, numberOfColumns >::FullArrayMatrix (const FullArrayMatrix<scalar, numberOfRows, numberOfColumns > &matriceInput,bool forceColumnBased):onlyColumnBased(forceColumnBased){
cout<<endl<<endl<<matriceInput.getOnlyColumnBased()<<onlyColumnBased;
if (!onlyColumnBased) {
for (int i=1; i< numberOfRows +1; i++) {
for (int j=1; j< numberOfColumns +1; j++) {
(*this)(i,j)=inputMatrix.horizontalMatrixArray[j-1][i-1];
}
}
} else {
for (int i=1; i< numberOfColumns +1; i++) {
cout<<endl<<"column "<<i<<" "<<inputMatrix.getOnlyColumnBased();
for (int j=1; j< numberOfRows +1; j++) {
cout<<endl<<"row "<<j<<" "<<inputMatrix.getOnlyColumnBased();
(*this)(i,j)=inputMatrix.verticalMatrixArray[i-1][j-1];
}
}
}
cout<<inputMatrix.getOnlyColumnBased();
}
I have put some cout to notice when onlyColumnBased changes and it seems to change in the 1st column, 3rd row.
This is the main:
FullArrayMatrix<double, 10, 1> full1(true);
full1.print();
FullArrayMatrix<double, 10, 1> full2(full1,true);
full1.print();
This is the output:
--
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
--
11
column 1 1
row 1 1
row 2 1
row 3 1
row 4 0
row 5 0
row 6 0
row 7 0
row 8 0
row 9 0
row 10 0
0
--
| 0 0 0 0 0 0 0 0 0 0 |
--
I really dont't have idea of the problem!