Don't know what generates this 'Segmentation Fault' error - c++

Question

I'm currently making a simulation of an autonomous car for my AI class. The car's constructor receives the board as a parameter so it can set the position of the car and add the first node to the search tree, so it can search an optimum path from the Starting Position to the Finishing Position. The thing is, the board generates without any problem, but when I try to pass it to the car's constructor, it results in a Segmentation fault (core dumped) error.
I used a debugger (gdb), ran the code in it and made a back-trace; and the problem came from here:
void node_c::add_child(node_c* chld)
{ int i;
for (i = 0; i < MAX_CHILDREN; i++)
{ if (children_[i] == NULL) //This line's the problem
break;
}
if (children_[i] != NULL)
{ cout << endl << "You can't add any more children." << endl;
return;
}
else children_[i] = chld;
}
Note: 'children_' contains a maximum of 4 children of a search_tree's node, and is a custom vector_c class I had to make.
This is the operator that fails and the function it calls:
template <typename TDato>
TDato& vector_c<TDato>::operator [](int position) { return get_data(position); }
template <typename TDato>
TDato& vector_c<TDato>::get_data(int a) const { return data_[a]; }
I thought that it might be a type error in the comparison if (children_[i] == NULL) so I made a custom operator that returned an object (TDato), not a reference to an object (TDato&), but it didn't work.
I can't imagine what could be causing this and/or how to solve it.
Thanks in advance.
Edit 1: Here's a google drive link to the project as even a minimal reproducible example would be too large to be easy to read in a Stack Overflow question. It's not very big, I promise (less than 1 MB).
Edit 2: Here's the most I could do to make the reproducible example minimal, as the question got closed for not including it.
main.cpp
#include "../include/board_s.hpp"
#include "../include/car_c.hpp"
using namespace std;
int main(void)
{ board_s<int> board(20, 20);
board.file_depiction();
car_c car(board);
board.write(cout);
return 0;
}
Here, the problem comes when the constructor of car_c is called. It should create an car_c object.
board_c.hpp
#ifndef __BOARD_S__
#define __BOARD_S__
#include <cstdio>
#include <iostream>
#include <cstring>
#include <random>
#include <fstream>
#include <utility>
#include "matrix_c.hpp"
#include "tree_c.hpp"
using namespace std;
template <typename TDato = int>
class board_s: public matrix_c<TDato>
{ private:
pair<int, int> starting_pos;
pair<int, int> finishing_pos;
public:
board_s(int, int);
~board_s(void);
pair<int, int> get_start(void);
void file_depiction(void); //Generates obstacles and starting/finishing points as depicted in board_depiction.txt.
virtual ostream& write(ostream&);
int distance(pair<int, int>&) const; //Returns the distance from a given position to the finishing point
private:
bool object_setter(string, int&, int&);
int object_identifier(string&) const; //Given the name of the object ("NEW OBSTACLE" [1], "STARTING POSITION" [2] or "FINISHING POSITION" [3]) returns it's code
};
template class board_s<int>;
#endif
board_c.cpp
#include "../include/board_s.hpp"
#include "matrix_c.cpp"
using namespace std;
//The constructor fills the board with empty boxes.
template <typename TDato>
board_s<TDato>::board_s(int m, int n):
matrix_c<TDato>::matrix_c(m + 2, n + 2)
{ for(int i = 1; i < m; i++)
for(int j = 1; j < n; j++)
matrix_c<TDato>::at(i, j) = 0;
for(int i = 0; i < n + 2; i++)
{ matrix_c<TDato>::at(0, i) = 1;
matrix_c<TDato>::at(m + 1, i) = 1;
}
for(int i = 0; i < m + 2; i++)
{ matrix_c<TDato>::at(i, 0) = 1;
matrix_c<TDato>::at(i, n + 1) = 1;
}
starting_pos.first = 0;
starting_pos.second = 0;
finishing_pos.first = 0;
finishing_pos.second = 0;
}
template <typename TDato>
board_s<TDato>::~board_s(void){}
template <typename TDato>
pair<int, int> board_s<TDato>::get_start(void) { return starting_pos; }
template <typename TDato>
void board_s<TDato>::file_depiction(void)
{ string line;
int x, y, i;
std::ifstream bd;
bd.open("board_depiction.txt");
if (bd.is_open())
{ getline(bd, line);
getline(bd, line);
i = line.size() - 1;
y = matrix_c<TDato>::strtoi(line, i);
i--;
x = matrix_c<TDato>::strtoi(line, i);
matrix_c<TDato>::resize(x + 2, y + 2);
getline(bd, line);
getline(bd, line);
i = line.size() - 1;
y = matrix_c<TDato>::strtoi(line, i);
i--;
x = matrix_c<TDato>::strtoi(line, i);
object_setter("STARTING POSITION", x, y);
getline(bd, line);
getline(bd, line);
i = line.size() - 1;
y = matrix_c<TDato>::strtoi(line, i);
i--;
x = matrix_c<TDato>::strtoi(line, i);
object_setter("FINISHING POSITION", x, y);
while (getline(bd, line))
if (line[0] != 'O')
{ i = line.size() - 1;
y = matrix_c<TDato>::strtoi(line, i);
i--;
x = matrix_c<TDato>::strtoi(line, i);
object_setter("NEW OBSTACLE", x, y);
}
}
else cout << "ERROR";
}
template <typename TDato>
ostream& board_s<TDato>::write(ostream& os)
{ int temp = matrix_c<TDato>::get_n() - 2 + (4 * (matrix_c<TDato>::get_n() - 2));
os << " ";
for (int i = 1; i < temp; i++)
os << "_";
os << " " << endl << "|";
for (int i = 1; i < matrix_c<TDato>::get_m() - 1; i++)
{ for (int j = 0; j < 2; j++)
{ for (int k = 1; k < matrix_c<TDato>::get_n() - 1; k++)
switch (matrix_c<TDato>::at(i, k))
{ case 1:
os << "████|";
break;
case 2:
if (j == 0)
os << " CC |";
else os << "_CC_|";
break;
case 3:
if (j == 0)
os << " FF |";
else os << "_FF_|";
break;
default:
if (j == 0)
os << " |";
else os << "____|";
}
os << endl;
if (j == 0) os << "|";
}
if (i < matrix_c<TDato>::get_m() - 2) os << "|";
}
os << endl;
return os;
}
template <typename TDato>
int board_s<TDato>::distance(pair<int, int>& pos) const
{ int d = (finishing_pos.first - pos.first) + (finishing_pos.second - pos.second);
if (d < 0) return (d * (-1));
else return d;
}
template <typename TDato>
bool board_s<TDato>::object_setter(string name, int &x, int &y)
{ if((x > 0) && (x < matrix_c<TDato>::get_m() - 1) && (y > 0) && (y < matrix_c<TDato>::get_n() - 1) && (matrix_c<TDato>::at(x, y) == 0))
{ matrix_c<TDato>::at(x, y) = object_identifier(name);
cout << endl << endl << "The " << name << " has been set in (" << x << ", " << y << ")" << endl;
if (name == "STARTING POSITION")
{ starting_pos.first = x;
starting_pos.second = y;
}
else if (name == "FINISHING POSITION")
{ finishing_pos.first = x;
finishing_pos.second = y;
}
return true;
}
else
{ cout << endl << "The coordinates that you intriduced were out of reach or the position wasn't free." << endl;
return false;
}
}
template <typename TDato>
int board_s<TDato>::object_identifier(string &name) const
{ if (name == "NEW OBSTACLE")
return 1;
else if (name == "STARTING POSITION")
return 2;
else if (name == "FINISHING POSITION")
return 3;
else return 0;
}
matrix_c.hpp
#ifndef __MATRIX_C__
#define __MATRIX_C__
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <cstring>
#include "vector_c.hpp"
using namespace std;
template <typename TDato>
class matrix_c //Template matrix class implemented with a vector.
{ private:
int m_;
int n_;
vector_c<TDato> v_;
public:
matrix_c(void); //Empty constructor
matrix_c(int, int); //Constructor with dimensions
~matrix_c(void);
void resize(int, int);
TDato& at (int, int); //Redirects to position (x, y)
virtual TDato& operator()(int, int); //Operator for at(int, int)
int get_m(void) const;
int get_n(void) const;
private:
int pos(int, int);
protected:
int ctoi(char&) const;
int strtoi(string&, int&) const;
};
#endif
matrix_c.cpp
#include "../include/matrix_c.hpp"
using namespace std;
template <typename TDato>
matrix_c<TDato>::matrix_c(void):
m_(0),
n_(0),
v_() {}
template <typename TDato>
matrix_c<TDato>::matrix_c(int m, int n):
m_(m),
n_(n),
v_(m * n) {}
template <typename TDato>
matrix_c<TDato>::~matrix_c(void) {}
template <typename TDato>
void matrix_c<TDato>::resize(int m, int n)
{ v_.resize(m * n);
m_ = m;
n_ = n;
}
template <typename TDato>
TDato& matrix_c<TDato>::at(int i, int j) { return v_[(pos(i,j))]; }
template <typename TDato>
TDato& matrix_c<TDato>::operator()(int i, int j) { return at(i,j); }
template <typename TDato>
int matrix_c<TDato>::get_m(void) const { return m_; }
template <typename TDato>
int matrix_c<TDato>::get_n(void) const { return n_; }
template <typename TDato>
int matrix_c<TDato>::pos(int i, int j) { return ((n_ * i) + j); }
template <typename TDato>
int matrix_c<TDato>::ctoi(char &c) const
{ int n = c;
return n - 48;
}
template <typename TDato>
int matrix_c<TDato>::strtoi(string &s, int& i) const
{ int n = 0;
int mult = 1;
while ((s[i] != ' ') && (i >= 0))
{ n += ctoi(s[i]) * mult;
mult *= 10;
i--;
}
return n;
}
template class matrix_c<int>;
vector_c.hpp
#ifndef __VECTOR_C__
#define __VECTOR_C__
#include <iostream>
#include <cstdio>
#include <cassert>
using namespace std;
template <typename TDato>
class vector_c
{ private:
int sz_;
TDato* data_;
public:
vector_c(void); //Empty constructor
vector_c(int); //Constructor with size
~vector_c(void);
TDato& get_data(int) const;
void set_data(TDato&, int);
ostream& write(ostream&) const;
TDato& operator [](int);
void resize(int);
private:
void new_vector(void);
void del_vector(void);
};
#endif
vector_c.cpp
#include "../include/vector_c.hpp"
#include "../include/node_c.hpp"
using namespace std;
template <typename TDato>
vector_c<TDato>::vector_c(void):
sz_(0),
data_(NULL) {}
template <typename TDato>
vector_c<TDato>::vector_c(int size):
sz_(size),
data_(new TDato[sz_]) {}
template <typename TDato>
vector_c<TDato>::~vector_c(void)
{ delete[] data_;
data_ = NULL;
}
template <typename TDato>
TDato& vector_c<TDato>::get_data(int a) const { return data_[a]; }
template <typename TDato>
void vector_c<TDato>::set_data(TDato& dat, int a) { data_[a] = dat;}
template <typename TDato>
TDato& vector_c<TDato>::operator [](int position) { return get_data(position); }
template <typename TDato>
void vector_c<TDato>::resize(int sz)
{ del_vector();
sz_ = sz;
new_vector();
}
template <typename TDato>
void vector_c<TDato>::new_vector(void){
data_ = new TDato[sz_];
}
template <typename TDato>
void vector_c<TDato>::del_vector(void)
{ if (data_ != NULL){
delete [] data_;
data_ = NULL;
}
}
template class vector_c<int>;
template class vector_c<node_c*>;
node_c.hpp
#define MAX_CHILDREN 4
#ifndef __NODE_C__
#define __NODE_C__
#include <iostream>
#include <cstdio>
#include <cassert>
#include "vector_c.hpp"
using namespace std;
class node_c
{ private:
node_c* parent_;
vector_c< node_c* > children_;
pair<pair<int, int>, int> data_;
public:
node_c(void);
node_c(int &x, int &y, int &cost);
node_c(pair<pair<int, int>, int>&);
~node_c(void);
void add_child(node_c*);
};
#endif
node_c.cpp
#include "../include/node_c.hpp"
using namespace std;
node_c::node_c(void):
parent_(NULL)
{ for (int i = 0; i < MAX_CHILDREN; i++)
children_[i] = NULL;
data_.first.first = 0;
data_.first.second = 0;
data_.second = 0;
}
node_c::node_c(int &x, int &y, int &cost):
parent_(NULL)
{ for (int i = 0; i < MAX_CHILDREN; i++)
children_[i] = NULL;
data_.first.first = x;
data_.first.second = y;
data_.second = cost;
}
node_c::node_c(pair<pair<int, int>, int> &dat):
parent_(NULL),
data_(dat)
{ for (int i = 0; i < MAX_CHILDREN; i++)
children_[i] = NULL;
}
node_c::~node_c(void)
{ parent_ = NULL;
for (int i = 0; i < MAX_CHILDREN; i++)
children_[i] = NULL;
data_.first.first = 0;
data_.first.second = 0;
data_.second = 0;
}
void node_c::add_child(node_c* chld)
{ int i;
for (i = 0; i < MAX_CHILDREN; i++)
{ if (children_[i] == NULL)
break;
}
if (children_[i] != NULL)
{ cout << endl << "You can't add any more children." << endl;
return;
}
else children_[i] = chld;
}
tree_c.hpp
#ifndef __TREE_C__
#define __TREE_C__
#include "node_c.hpp"
using namespace std;
class tree_c
{ private:
node_c* root_;
int depth_;
public:
tree_c(void);
tree_c(node_c*);
node_c* add_node(node_c*, int&, int&, int);
};
#endif
tree_c.cpp
#include "../include/tree_c.hpp"
using namespace std;
tree_c::tree_c(void):
root_(NULL),
depth_(0) {}
tree_c::tree_c(node_c* root):
root_(root),
depth_(1) {}
node_c* tree_c::add_node(node_c* parent, int& x, int& y, int cost)
{ node_c* node = new node_c(x, y, cost);
parent->add_child(node);
}
car_c.hpp
#ifndef __CAR_C__
#define __CAR_C__
#include <iostream>
#include <cstdio>
#include <cassert>
#include "tree_c.hpp"
#include "board_s.hpp"
using namespace std;
class car_c
{ private:
tree_c tree_;
pair<int, int> pos_;
matrix_c<int> visited_;
public:
car_c(void);
car_c(board_s<int>&);
~car_c(void);
};
#endif
car_c.cpp
#include "../include/car_c.hpp"
using namespace std;
car_c::car_c(void):
tree_(NULL)
{ pos_.first = 0;
pos_.second = 0;
}
car_c::car_c(board_s<int>& board):
pos_(board.get_start()),
tree_(tree_.add_node(NULL, pos_.first, pos_.second, 0))
{ visited_(pos_.first, pos_.second) = 1; }
car_c::~car_c(void) {}
Debugging information:
Program received signal SIGSEGV, Segmentation fault.
0x0000000000401cc2 in node_c::node_c (this=0x6187d0, x=#0x7ffffffeddf0: 8, y=#0x7ffffffeddf4: 0,
cost=#0x7ffffffedd2c: 0) at src/node_c.cpp:20
20 children_[i] = NULL;
(gdb) bt
#0 0x0000000000401cc2 in node_c::node_c (this=0x6187d0, x=#0x7ffffffeddf0: 8, y=#0x7ffffffeddf4: 0,
cost=#0x7ffffffedd2c: 0) at src/node_c.cpp:20
#1 0x0000000000402007 in tree_c::add_node (this=0x7ffffffedde0, parent=0x0, x=#0x7ffffffeddf0: 8,
y=#0x7ffffffeddf4: 0, cost=0) at src/tree_c.cpp:16
#2 0x0000000000402df6 in car_c::car_c (this=0x7ffffffedde0, board=...) at src/car_c.cpp:15
#3 0x0000000000401403 in main () at src/main.cpp:11
Sorry for the length of my question, but this is the minimal reproducible example I was able to make. If you know another way to recreate my error, let me know so I can improve this.