El cifrado

 #include <iostream>

#include<vector>

#include<math.h>

using namespace std;

void cifrado(vector<string>& s,int k){

  int val;

  int s_size=s.size();

  for(int i=0;i<s_size;i++){

     int s_0=s[i].size();

     for(int j=0;j<s_0;j++){

      if(s[i].at(j)>=97){

          val=s[i].at(j)-'a';

          val=(val+k)%26;

          

          s[i].at(j)='a'+val;

      }

      if(s[i].at(j)<97){

          val=s[i].at(j)-'A';

          val=(val+k)%26;

          s[i].at(j)='A'+val;

      }

  }    

  }

}

int main() {

  /* This is a program to take an input

   * string from the user and encrypt it by 

   * My personal method.

   *

   */

   cout<<"Enter the number of words that you want to input and encrypt."<<endl;

   int n;

   cin>>n;

   cout<<"Enter the sentence which you want to encrypt."<<endl;

   vector<string> str(n);

   for(int i=0;i<n;i++){

       cin>>str[i];

   }

   cout<<"Now enter the level of encryption, from 0 to 30. "<<endl;

   int k;

   cin>>k;

   cout<<"The encrypted string is ";

   cifrado(str,k);

  for(string s:str){

      cout<<s<<" ";

  }cout<<endl;

    return 0;

}