#include <iostream>
#include <iomanip>
 
using namespace std;
 
int crypt(int v, bool encrypt) {
	if (v<0 || v>9999) return -1;
 
	int d = encrypt? 7 : 3;
 
	char digits[4];
 
	for(int i=3; i>=0; i--,v/=10) digits[i] = (v % 10 + d) % 10;
 
	swap(digits[0],digits[2]); swap(digits[1],digits[3]);
 
	int r = 0;
	for(int i=3, m=1; i>=0; i--,m*=10) r += digits[i] * m;
 
	return r;
}
 
int main() {
	int e = crypt(8765, true);	//encrypt
	int d = crypt(e, false);	//decrypt
 
	cout <<
		"Encrypted:\t" << setw(4) << setfill('0') << e << endl << 
		"Decrypted:\t" << d << endl;
 
	return 0;
}

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