How Can I change the code to ask user to input the key instead of write it directly into the code, like Vigenere cipher("VIGENERECIPHER").

 #include  #include  using namespace std; class Vigenere { public: string key; Vigenere(string key) { for(int i = 0; i < key.size(); ++i) { if(key[i] >= 'A' && key[i] <= 'Z') this->key += key[i]; else if(key[i] >= 'a' && key[i] <= 'z') this->key += key[i] + 'A' - 'a'; } } string encrypt(string text) { string out; for(int i = 0, j = 0; i < text.length(); ++i) { char c = text[i]; if(c >= 'a' && c <= 'z') c += 'A' - 'a'; else if(c < 'A' || c > 'Z') continue; out += (c + key[j] - 2*'A') % 26 + 'A'; j = (j + 1) % key.length(); } return out; } string decrypt(string text) { string out; for(int i = 0, j = 0; i < text.length(); ++i) { char c = text[i]; if(c >= 'a' && c <= 'z') c += 'A' - 'a'; else if(c < 'A' || c > 'Z') continue; out += (c - key[j] + 26) % 26 + 'A'; j = (j + 1) % key.length(); } return out; } }; int main() { Vigenere cipher("VIGENERECIPHER"); string original = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"; string encrypted = cipher.encrypt(original); string decrypted = cipher.decrypt(encrypted); cout << original << endl; cout << "Encrypted: " << encrypted << endl; cout << "Decrypted: " << decrypted << endl; }