C++ Tictactoe：从文件加载存储

在加载电路板 struct 之前还有一个额外的fgetc(Load)，它可能应该跳过挂起的换行符，但由于格式字符串中的尾随空格，fscanf(Load, "%d %d ", ...)已经使用了这个换行符.

还要注意，您必须将指针传递给fscanf，而不是值*roundcount、*x和*y.指定值和指向值的指针使用相同的标识符是非常令人困惑的.要避免这种容易出错的方法，请对从文件中读取的值使用局部变量，并仅在成功完成后才将它们存储到调用方的变量中.

为便于故障排除，请测试所有错误 case 并输出信息性错误消息.

以下是修改后的版本:

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

int FileLoad(char ***pboard, int *pcols, int *prows,
             int *proundcount, const char *filename)
{
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        fprintf(stderr, "FileLoad: cannot open file %s: %s\n", filename, strerror(errno));
        return -1;
    }

    int rows, cols, roundcount;
    char eol[2];

    // read exactly 3 numbers and a newline.
    if (fscanf(fp, "%d %d %d%1[\n]", &roundcount, &cols, &rows, eol) != 4) {
        fprintf(stderr, "FileLoad: file %s: invalid format\n", filename);
        fclose(fp);
        return -1;
    }

    char **board = (char **)malloc(rows * sizeof(char *));
    char *p = (char *)malloc(sizeof(char) * rows * cols));
    if (board == NULL || p == NULL) {
        fprintf(stderr, "FileLoad: file %s: allocation error\n", filename);
        free(board);
        free(p);
        fclose(fp);
        return -1;
    }
    for (int i = 0; i < rows; ++i) {
        board[i] = p + i * cols;
    }

    // Read the game board
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            // should be a space, an 'X' or an 'O'
            board[i][j] = fgetc(fp);
        }
        if (fgetc(fp) != '\n') {
            fprintf(stderr, "FileLoad: file %s: invalid contents\n", filename);
            free(board);
            free(p);
            fclose(fp);
            return -1;
        }
    }
    fclose(fp);
    *poard = board;
    *proundcount = roundcount;
    *pcols = cols;
    *prows = rows;
    return 0;
}