#include <iostream>
#include <cstring>
#include <string>

using namespace std;

char encoded(char emsg,int code);
char decoded(char dmsg,int code);

int main ()
{
	char msg[100];
	char key[100];
	char codedmsg[100];
	char decodedmsg[100];
	char *n = msg;
	int keycode;
	int i;
	int msglength;

	cout << "Enter message : ";
	gets(msg);

	cout << endl << "Enter key : ";
	gets(key);

	msglength = strlen(msg);
	keycode = int(key);

	for (i=0;i<msglength;i++)
	{
		codedmsg[i] = encoded(msg[i],keycode);
	}

	for (i=0;i<msglength;i++)
	{
		decodedmsg[i] = decoded(codedmsg[i],keycode);
	}

	cout << endl << "Encoded message : " << codedmsg;

	cout << endl << "Decoded message : " << decodedmsg << endl;

	return 0;
}

char encoded(char emsg,int code)
{
	char newbyte;

	newbyte = emsg + code;

	return newbyte;
}

char decoded(char dmsg,int code)
{
	char oldbyte;

	oldbyte = dmsg - code;

	return oldbyte;
}