~cpp
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream fin("source.txt");
ofstream fout("source_enc.txt");
char input;
int i;
char data[100] = {'0', };
int count = 0;
cout << "원본값" << endl;
while(true)
{
fin.get(input);
if (fin.eof())
break;
cout << input;
data[count] = input;
count++;
}
data[count] = NULL;
cout << endl;
int key;
cout << "Key 입력 : ";
cin >> key;
cout << "암호화" << endl;
for (i = 0; data[i] != NULL ;i++)
{
data[i] += key;
fout << char(data[i]);
cout << char(data[i]);
}
cout << endl;
fout << endl;
cout << "복호화" << endl;
for (i = 0; data[i] != NULL ;i++)
{
data[i] -= key;
fout << char(data[i]);
cout << char(data[i]);
}
cout << endl;
return 0;
}