Caesar 密码解密 - GESP 三级

#include #include using namespace std;

string decrypt(string cipher) { string plaintext = ""; for (int i = 0; i < cipher.length(); i++) { if (isalpha(cipher[i])) { char decryptedChar = cipher[i] - 5; if (decryptedChar < 'A') { decryptedChar += 26; } plaintext += decryptedChar; } else { plaintext += cipher[i]; } } return plaintext; }

int main() { string cipher; getline(cin, cipher); string plaintext = decrypt(cipher); cout << plaintext << endl; return 0; }