尝试与2D阵列C++交互时出现分段故障

Question

我正试图通过Board类与2D数组进行交互。然而，在运行包含以下代码的主文件时，我遇到了分段错误：

#include "Board.h"
int main(int argc, char** argv)
{
int height = 0;
int width = 0;
int pop_density = 0.8;
Board* c = new Board(height,width);
c->print();
c->populate(pop_density);
c->print();
//for (i )
cout << c->read_char_at_index(1,2) << endl;
delete c;
return 0;
}

这是Board.cpp代码：

#include "Board.h"
//in board: make a fucntion that pulls from file
Board::Board(int h, int w)
{
m_height = h;
m_width = w;
m_array = new char* [m_height];
for (int i = 0; i < m_height; ++i)
{
m_array[i] = new char[m_width];
for (int j = 0; j < m_width; ++j)
{
m_array[i][j] = '-';
}
}
cout << "Made board" << endl;
}
Board::~Board()
{
for (int i = 0; i < this->m_height; ++i)
{
delete[] this->m_array[i];
}
delete[] this->m_array;
cout << "Destructed Board" << endl;
}
void Board::print()
{
for (int i = 0; i < this->m_height; ++i)
{
for (int j = 0; j < this->m_width; ++j)
{
cout << this->m_array[i][j] << " ";
}
cout << endl;
}
}
void Board:: populate(double density)
{
//seeding rand with time
srand(time(NULL));
int totalCells = this->m_height * this->m_width;
int cellsToFill = round(totalCells * density);
int cellsFilled = 0;
for (int i = 0; i < cellsToFill; ++i)
{
int randomRow = rand() % this->m_height;
int randomColumn = rand() % this->m_width;
this->m_array[randomRow][randomColumn] = 'X';
}
}
void Board:: write_char_at_index(int height, int width, char z)
{
cout << "pre" << endl;
cout << height << " " << width << endl;
m_array[height][width] = z;
cout << "Wrote" << endl;
}
char Board:: read_char_at_index(int height, int width)
{
return m_array[height][width];
cout << "read" << endl;
}

以及Board。h代码：

#ifndef BOARD_H
#define BOARD_H
#include <iostream>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
using namespace std;
//This class is used to make a Board object
class Board
{
public:
Board(int h, int w);
~Board();
void print(); // Prints the board to cout
void populate(double density); // Populates board based on density input
void write_char_at_index(int height, int width, char z);
char read_char_at_index(int height, int width);
private:
char** m_array; // 2D array dynamically allocated during runtime
int m_height;
int m_width;
};
#endif

任何帮助或建议都会很好，因为我已经问了两位同学，他们不确定问题出在哪里。我确信我试图分配char值的索引没有越界。

Answer 1

read_char_at_index的输入参数在主函数中为(1,2(。但是，Board对象c的高度为0，宽度为0。可以将高度和宽度的值修改为足够大的值，例如10、10。

int height = 10;
int width = 10;
int pop_density = 0.8;
Board* c = new Board(height, width);
c->print();
c->populate(pop_density);
c->print();
cout << c->read_char_at_index(1, 2) << endl;

程序可以在没有分段故障的情况下运行。

注意：函数"write_char_at_index"one_answers"read_char_at_index"可能会检查输入值(高度和宽度(，以确保对m_array成员的访问是安全的。

if (height >= this->m_height || width >= this->m_width)
{
return;
}