~cpp
#include <iostream>
#include <fstream>
using namespace std;
void main()
{
ifstream fin("xm.txt");
ofstream fout("out.txt");
char arr[100];
int key=30, count=0, i=0,temp;
while(!fin.eof())
{
fin.get(arr[i]);
i++;
count++;
}
for(i=0;i<count;i++)
{
int temp = int (arr[i]) + key;
arr[i]=char (temp);
fout << arr[i];
cout << arr[i];
}
cout << endl;
for(i=0;i<count;i++)
{
temp = (int (arr[i]) - key +256)%256;
arr[i]=char (temp);
fout << arr[i];
cout << arr[i];
}
cout << endl;
}