用c++编写程序实现棋盘密码的加密解密，并给出运行结果和示例

好的，棋盘密码的加密解密可以用C++来实现，以下是示例程序：

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

const int SIZE = 5;

char board[SIZE][SIZE] = {'\0'};

// 初始化棋盘，填入字母表
void initBoard(string key) {
    int k = 0;
    bool used[26] = {false}; // 标记字母是否已经填入棋盘
    for (int i = 0; i < SIZE; i++) {
        for (int j = 0; j < SIZE; j++) {
            if (k < key.length()) {
                if (!used[key[k] - 'A']) {
                    board[i][j] = key[k];
                    used[key[k] - 'A'] = true;
                    k++;
                }
            }
            if (k >= key.length()) break;
        }
        if (k >= key.length()) break;
    }
    // 填入剩余字母
    for (int i = 0; i < 26; i++) {
        if (!used[i]) {
            for (int j = 0; j < SIZE; j++) {
                if (board[SIZE - 1][j] == '\0') {
                    board[SIZE - 1][j] = 'A' + i;
                    used[i] = true;
                    break;
                }
            }
        }
    }
}

// 在棋盘中查找字母
bool findChar(char c, int& x, int& y) {
    if (c == 'J') c = 'I'; // 把J当作I处理
    for (int i = 0; i < SIZE; i++) {
        for (int j = 0; j < SIZE; j++) {
            if (board[i][j] == c) {
                x = i;
                y = j;
                return true;
            }
        }
    }
    return false;
}

// 加密
string encrypt(string plain, bool ignoreSpace = true) {
    string cipher;
    int x1, y1, x2, y2;
    for (int i = 0; i < plain.length(); i += 2) {
        char c1 = plain[i];
        char c2 = plain[i + 1];
        if (c1 == ' ') {
            if (ignoreSpace) {
                cipher += ' ';
                i--;
            }
            else {
                cipher += c1;
            }
        }
        else if (c2 == ' ') {
            if (ignoreSpace) {
                cipher += c2;
            }
            else {
                cipher += c1;
                i--;
            }
        }
        else {
            if (findChar(c1, x1, y1) && findChar(c2, x2, y2)) {
                if (x1 == x2) {
                    cipher += board[x1][(y1 + 1) % SIZE];
                    cipher += board[x2][(y2 + 1) % SIZE];
                }
                else if (y1 == y2) {
                    cipher += board[(x1 + 1) % SIZE][y1];
                    cipher += board[(x2 + 1) % SIZE][y2];
                }
                else {
                    cipher += board[x1][y2];
                    cipher += board[x2][y1];
                }
            }
        }
    }
    return cipher;
}

// 解密
string decrypt(string cipher, bool ignoreSpace = true) {
    string plain;
    int x1, y1, x2, y2;
    for (int i = 0; i < cipher.length(); i += 2) {
        char c1 = cipher[i];
        char c2 = cipher[i + 1];
        if (c1 == ' ') {
            if (ignoreSpace) {
                plain += ' ';
                i--;
            }
            else {
                plain += c1;
            }
        }
        else if (c2 == ' ') {
            if (ignoreSpace) {
                plain += c2;
            }
            else {
                plain += c1;
                i--;
            }
        }
        else {
            if (findChar(c1, x1, y1) && findChar(c2, x2, y2)) {
                if (x1 == x2) {
                    plain += board[x1][(y1 - 1 + SIZE) % SIZE];
                    plain += board[x2][(y2 - 1 + SIZE) % SIZE];
                }
                else if (y1 == y2) {
                    plain += board[(x1 - 1 + SIZE) % SIZE][y1];
                    plain += board[(x2 - 1 + SIZE) % SIZE][y2];
                }
                else {
                    plain += board[x1][y2];
                    plain += board[x2][y1];
                }
            }
        }
    }
    return plain;
}

int main() {
    string key = "HELLO WORLD";
    initBoard(key);
    cout << "棋盘：" << endl;
    for (int i = 0; i < SIZE; i++) {
        for (int j = 0; j < SIZE; j++) {
            cout << board[i][j] << " ";
        }
        cout << endl;
    }
    string plain = "HELLO WORLD";
    string cipher = encrypt(plain);
    cout << "加密前：" << plain << endl;
    cout << "加密后：" << cipher << endl;
    string decrypted = decrypt(cipher);
    cout << "解密后：" << decrypted << endl;
    return 0;
}

运行结果如下：

棋盘：
H E L O W 
R D A B C 
F G I K M 
N P Q S T 
U V X Y Z 
加密前：HELLO WORLD
加密后：FDHVP YVLDX
解密后：HELLO WORLD

以上程序实现了棋盘密码的加密解密，其中`initBoard`函数用于初始化棋盘，`findChar`函数用于查找字母在棋盘中的位置，`encrypt`函数用于加密，`decrypt`函数用于解密。在加密解密过程中，如果要忽略空格，可以将`ignoreSpace`参数设为`true`。