crypt.cpp

#include<iostream>
using namespace std;
string get_key(string str, string key){
    if(key.size() >= str.size())
        return key;
    else{
        int str_size = str.size()-key.size();
        int key_size = key.size(); 
        while(str_size >= key_size){
            key += key;
            str_size -= key_size;
        }
        key += key.substr(0, str_size);
        return key;
    }
}

string encrypt_pass(string str, string key){
    string temp = "";
    for(int i=0;i<str.size();i++)
        temp += (char) (((int)str[i]-'A' + (int)key[i]-'A') % 26) + 'A';
    return temp;
}
 
int main(){
    string password;
    cin>>password;
    string key = "HELLO";
    key = get_key(password, key);
    string encrypt = encryption(plaintext, key);
    cout<<" encrypted password: "<< encrypt <<endl;
    return 0;
}