尝试将字符分配给二维字符数组时，表示数组值的整数在 for 循环中递增

Question

在我的程序中，我试图从 .txt 文件输入字符并将它们分配给二维字符数组以形成迷宫。此代码的预期结果是：

xxxxxxx
xA...Bx
xxxxxxx

然而，当我认为在每个循环开始时 Column 应该为 0 时，我却被警告 Column 大于大小（定义为 30）。无论什么 Column 等于 Size 并且我不确定为什么。我已经包含了下面的代码。我是初级程序员，所以如果您有任何建议，请尽可能简单。非常感谢，本

#include<fstream>
#include<iostream>
#include<string>
#include <vector>
//Maze Size
#define SIZE 30
using namespace std;

void readMaze(string fileName);

void inputMaze();

int main()
{
    inputMaze();   
}

void readMaze(string fileName)
{
    int rows;
    int columns = 0;
    //vector<vector<char>> maze;    
    char maze[SIZE][SIZE];
    ifstream input(fileName);
    char data;
    while (input.get(data))   //While loop used to store each individual data to the string.
    {

        for (int rows = 0; rows < 20; rows++)
        {
            columns = 0;
            while (data != '\n')
            {
                if (rows > SIZE)
                {
                    cout << "ROWS GREATER THAN SIZE";
                    break;
                }
                else if (columns > SIZE)
                {
                    cout << "COLUMNS GREATER THAN SIZE";
                    break;
                }
                else
                {
                    maze[rows][columns] = data;
                    columns++;
                    data = input.get();
                }
            }
                data = input.get();
            }
        }
        cout << "The Maze being solved is: " << endl;
        cout << maze << endl;
        input.close();
}


void inputMaze()
{
    string userinput;
    cout << "Plese input a .txt file name" << endl;
    cin >> userinput; //User inputs the name of a .txt file --> goes to readMaze()
    readMaze(userinput);
}

Answer 1

rows 在 readMaze 中未初始化使用，因此程序具有未定义的行为。此外，cout << maze << endl; 通过越界读取使程序具有未定义的行为。

考虑将 maze 改成 std::vector<std::vector<char>> 甚至 std::vector<std::string> 以使其更简单。

示例：

#include <algorithm>
#include <fstream>
#include <iostream>
#include <iterator>
#include <sstream>
#include <string>
#include <vector>

std::vector<std::string> readMaze(std::istream& input) {
    std::vector<std::string> maze;
    std::string line;

    while(std::getline(input, line)) { // read a complete line at a time
        maze.push_back(line);          // and save it in the vector 
    }

    return maze;
}

void inputMaze() {
    std::string userinput;
    std::cout << "Plese input a .txt file name\n";

    if(std::cin >> userinput) {
        std::ifstream is(userinput);
        if(is) {
            auto maze = readMaze(is);

            std::cout << "The Maze being solved is:\n";
            std::copy(maze.begin(), maze.end(),
                      std::ostream_iterator<std::string>(std::cout, "\n"));
        }
        // the file will be closed automatically when "is" goes out of scope
    }
}

int main() {
    inputMaze();   
}

尝试将字符分配给二维字符数组时，表示数组值的整数在 for 循环中递增

Interger representing a Array value is increasing within a for loop when trying to assign characters to a 2D Character array

c++

arrays

multidimensional-array

char

ifstream