Untitled

#include <iostream>
#include <fstream>
using namespace std;
int shifr(int a, int d) 
{
    int shifr1 = 0;
    int b = 1;
        while (a != 0) 
        {
            int c = a % 10;
            c = (c + d) % 10;  
            shifr1 += c * b;
            b *= 10;
            a /= 10;
        }
    return shifr1;
}
int main() 
{
    ifstream input("foo.txt");
    ofstream output("fooo.txt");
    if (!input.is_open() || !output.is_open()) 
       {
           cout << "ERROR" << endl;
           return 1;
       }
    int N, d;
    input >> N >> d;
    for (int i = 0; i < N; ++i) 
    {
        int a;
        input >> a;
        int shifr1 = shifr(a, d);
        output << shifr1 << endl;
    }
    input.close();
    output.close();
    return 0;
}