在C语言中如何创建存储{S2、R4}类字符串的不可修改二维数组？

你的需求是存储包含多字符的字符串（比如"S6"、"accept"），原有的char二维数组只能存单个字符，完全满足不了。最直接的替代方案是二维字符串数组，也可以根据场景选择结构体数组，以下是具体实现：

1. 字符指针二维数组（推荐，节省空间） #

用char*类型定义二维数组，每个元素指向字符串字面量，结构和原代码完全一致，只需要修改类型和初始化内容：

#include <stdio.h>

int main(void)
{
    char* parsing_table[12][9] = {
        {"0","0","0","0","0","0","0","0","0"},
        {"0","0","0","0","0","0","0","0","1"},
        {"0","0","0","0","S6","0","0","0","0"},
        {"0","0","0","0","0","R3","0","0","0"},
        {"0","R3","0","0","0","0","accept","0","0"},
        {"0","0","0","0","0","0","0","0","0"},
        {"0","0","0","0","0","R1","0","4","0"}, 
        {"0","0","S11","0","0","0","0","0","5"},
        {"0","0","0","0","S8","0","0","0","0"},
        {"0","R5","0","0","0","0","0","1","0"},
        {"0","0","0","0","0","0","0","0","0"},
        {"0","0","0","0","0","0","0","2","0"}
    };

    for(int i = 0; i < 12; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            printf("%s ", parsing_table[i][j]);
        }
        puts("");
    }
    return 0;
}

• 优点：不需要预先分配固定长度的字符数组，内存占用更高效，初始化和原结构完全匹配。
• 注意：字符串字面量是只读的，如果需要修改数组中的字符串，这种方式不适用。

2. 固定长度的三维char数组（支持修改） #

如果需要后续修改数组中的字符串内容，可以定义三维char数组，每个元素是固定长度的字符数组：

#include <stdio.h>
#include <string.h>

int main(void)
{
    // 第三维的10表示每个字符串最多存9个字符+1个结束符'\0'
    char parsing_table[12][9][10] = {0};
    
    // 初始化内容
    strcpy(parsing_table[1][8], "1");
    strcpy(parsing_table[2][4], "S6");
    strcpy(parsing_table[3][5], "R3");
    strcpy(parsing_table[4][1], "R3");
    strcpy(parsing_table[4][6], "accept");
    strcpy(parsing_table[6][5], "R1");
    strcpy(parsing_table[6][7], "4");
    strcpy(parsing_table[7][2], "S11");
    strcpy(parsing_table[7][8], "5");
    strcpy(parsing_table[8][4], "S8");
    strcpy(parsing_table[9][1], "R5");
    strcpy(parsing_table[9][7], "1");
    strcpy(parsing_table[11][7], "2");
    // 未初始化的元素默认是空字符串，可以根据需求补充

    for(int i = 0; i < 12; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            printf("%s ", parsing_table[i][j]);
        }
        puts("");
    }
    return 0;
}

• 优点：可以随时修改数组中的字符串内容（用strcpy等函数）。
• 缺点：需要预先定义字符串的最大长度，内存占用比指针数组高。

3. 结构体二维数组（适合复杂场景） #

如果每个元素除了字符串，还需要额外的元数据（比如标记是移进、规约还是接受），可以定义结构体：

#include <stdio.h>

typedef struct {
    char type; // 'S'=移进, 'R'=规约, 'A'=接受, 'N'=空
    int value; // 对应数字，空或接受时可以设为-1
} Action;

int main(void)
{
    Action parsing_table[12][9] = {0};
    
    // 初始化示例
    parsing_table[1][8] = (Action){'N', 1};
    parsing_table[2][4] = (Action){'S', 6};
    parsing_table[3][5] = (Action){'R', 3};
    parsing_table[4][6] = (Action){'A', -1};
    // 其他元素按需求初始化

    for(int i = 0; i < 12; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            switch(parsing_table[i][j].type) {
                case 'S': printf("S%d ", parsing_table[i][j].value); break;
                case 'R': printf("R%d ", parsing_table[i][j].value); break;
                case 'A': printf("accept "); break;
                case 'N': 
                    if(parsing_table[i][j].value != -1) 
                        printf("%d ", parsing_table[i][j].value);
                    else 
                        printf("0 ");
                    break;
            }
        }
        puts("");
    }
    return 0;
}

• 优点：结构化存储信息，便于后续逻辑处理，避免字符串解析的麻烦。
• 缺点：初始化和打印逻辑比字符串数组复杂。

内容的提问来源于stack exchange，提问作者Daghan