Untitled

#include <fstream>
#include <iostream>
#include <vector>

bool endsWith( const int number, const std::vector< int >& digits )
{
    int lastDigit = number % 10;

    for( const auto& digit : digits )
    {
        if( lastDigit == digit )
        {
            return true;
        }
    }

    return false;
}

int main()
{
    std::ifstream inputFile( "dane2.txt" );
    std::ofstream outputFile( "wynik2.txt" );

    std::vector< int > validEndDigits = { 0, 3, 8, 9 };

    if( inputFile.is_open() && outputFile.is_open() )
    {
        int number;
        while( inputFile >> number )
        {
            if( endsWith( number, validEndDigits ) )
            {
                outputFile << number << '\n';
            }
        }
        inputFile.close();
        outputFile.close();
    }
    else
    {
        std::cout << "Wystapil problem z plikiem do zapisu lub do odczytu\n";
        return -1;
    }

    return 0;
}