Printing an struct that includes an 2d array - c++

Question

EDITED
What I am trying to do is (after reading from file and putting the information in 2d array defined in a struct,that part works) call a method that finds out if there is any zeroes in the array and if so change it and prints it again. I know I´m missing pointers but I don't know where. Thanks in advance.
struct matrix{
const static int N=9;
int Ar[N][N];
};
void iprint(matrix s){ //my method to print the array
for(int i = 0; i < 9; i++) {
for(int j = 0; j < 9; j++) {
cout << (s).Ar[i][j] << ' ';
}
cout << endl;
}
}
bool annotation(matrix s, int row, int column, int num){
if(s.Ar[row][column] == 0){
(s).Ar[row][column] = num;
return true;
}
else if(s.Ar[row][column] != 0){
cout << "NO" << endl;
return false;
} else {
cout << "No" << endl;
return false;
}
iprint(s);
}
The array in first place :
0 0 6 5 0 0 1 0 0
4 0 0 0 0 2 0 0 9
0 0 0 0 3 0 0 0 8
0 7 0 1 0 0 5 0 0
0 8 0 0 0 0 0 6 0
0 0 3 0 9 0 0 4 0
2 0 0 0 4 0 0 0 0
9 0 0 7 0 0 0 0 3
0 0 5 0 0 8 2 0 0
The output that I get after those methods (calling the method annotation(s,1,1,2); )
2686428 0 0 2686524 8989288 4733208 0 0 -17974607
1 0 4201360 4662484 0 8989288 8989340 9005760 0
.
.
.
Im reading the array from a file,and the method is
bool readMatrix(matrix s){
ifstream f;
f.open("nuMatrix.txt");
if (f.is_open()) {
while(!f.eof()){
for(int i=0;i<9;i++){
for(int j=0;j<9;j++){
f>>(s).Ar[i][j];
}
}
}
f.close();
iprint(s);
return true;
}
else {
cerr << "NO";
return false;
}
}`

Answer 1

The matrix you're passing to readMatrix and annotation isn't modified by the functions.
You're passing the matrix by value, so you're only modifying a copy of it.
Change your functions to take a reference to a matrix:
bool annotation(matrix& s, int row, int column, int num)
bool readMatrix(matrix& s)