c++ the dynamic array of class allocation fails (memory leak) - c++

Question

edit1: add a running tiny version.
I wrote a cpp file including some classes. When I test it in a single file, everything works but when I link it with other c files, the data I stored in the array in the class changed. I know there must be something wrong with my memory allocation so I changed it into dynamic one using new
but cant figure out where or how to fix
work in single .cpp file
in a file called test.app
class Board
{
public:
int **grid;
bool done;
int result;
public:
Board()
{
grid = new int*[3];
for(int i = 0; i < 3; ++i){
grid[i] = new int[3];
}
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
grid[i][j]=0;
}
}
done=false;
result=0;
}
}
class Node
{
public:
Board **arr;
//double heuristic;
bool done;
int result;
int prevx, prevy;
int next_turn;
public:
Node()
{
arr = new Board*[3];
for(int i=0;i<3;i++)
{
arr[i] = new Board[3];
}
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
arr[i][j] = new Board();
}
}
done = false;
//heuristic=0;
result = 0;
prevx = -1;
prevy = -1;
next_turn=1;
}
}
and the code where thing go wrong:
Treenode *head; //treat as global variable
void agent_start( int this_player )
{
//nothing to do
//cout << "here all good" << endl;
head = new Treenode();
//cout << head << endl;
m = 0;
return;
}
int agent_second_move( int board_num, int prev_move )
{
for(int i=0;i<9;i++)
{
for(int j=0;j<9;j++)
{
if(head->arr[res_boardx][res_boardy].grid[cordx][cordy] == 1)
{
cout << "here cant print" << endl;
head->move2(i,j,-1);
cout << "here cant print" << endl;
}
else if(head->arr[res_boardx][res_boardy].grid[cordx][cordy] == -1)
{
cout << "here cant print" << endl;
head->move2(i,j,1);
}
}
}
in test.h
extern int port;
extern char *host;
#ifdef __cplusplus
extern "C" {
#endif
extern char *host;
#ifdef __cplusplus
}
#endif
#ifdef __cplusplus
extern "C" {
#endif
// parse command-line arguments
void agent_parse_args( int argc, char *argv[] );
// called at the beginning of a series of games
void agent_init();
// called at the beginning of each game
void agent_start( int this_player );
int agent_second_move(int board_num, int prev_move );
int agent_third_move(int board_num,int first_move,int prev_move);
int agent_next_move( int prev_move );
void agent_last_move( int prev_move );
// called at the end of each game
void agent_gameover( int result, int cause );
// called at the end of the series of games
void agent_cleanup();
#ifdef __cplusplus
}
#endif
in main.cpp
int main(int argc, char *argv[]){
agent_start(1);
int b = agent_second_move(1,1);
}
the output is:
[1] 26904 illegal hardware instruction
or
segmentation fault
before when I delared
class Node
{
public:
Board arr[3][3]; ///
in Node class.
the working version before which caused data in treenode changed
class Board
{
public:
int grid[3][3];
bool done;
int result;
public:
Board()
{
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
grid[i][j]=0;
}
}
done=false;
result=0;
}
}
class Node
{
public:
Board arr[3][3];
//double heuristic;
bool done;
int grid[3][3];
int result;
int prevx, prevy;
int next_turn;
public:
Node()
{
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
arr[i][j] = Board();
grid[i][j]=0;
}
}
done = false;
//heuristic=0;
result = 0;
prevx = -1;
prevy = -1;
next_turn=1;
}
}
Treenode *head;
head = new Treenode();
void print_map(){
for(int i=0;i<9;i++)
{
for(int j=0;j<9;j++)
{
int res_boardx, res_boardy, cordx, cordy;
res_boardx = (i-1)/3;
res_boardy = (i-1)%3;
cordx = (j-1)/3;
cordy = (j-1)%3;
cout << head->arr[res_boardx][res_boardy].grid[cordx][cordy];
}
cout << endl;
}
}
the 2D array printed out is below when I call print function outside this
file which is wrong since it should either be 1 or 0 or -1.
433000000
107312758200000000
000000000
000000000
000000000
000000000
00000-1000
000000000
000000000

Answer 1

You are not following the rule of 5. You have some memory allocation in constructor, so you need a non default destructor, to correctly free everything, as long as explicit move/copy constructors and assignment operators.
If possible, you should stick to standard containers like std::vector which handle all the corner cases for you.