C++ uždavinys. Mokymosi laikas

#include <iostream>
#include <fstream>
#include <string>

int dataCount = 0;
int Aval[20], Amin[20], Bval[20], Bmin[20];

int ReadFromDataFile()
{
    std::ifstream dataFile("data.txt");
    dataFile >> dataCount;

    for (int i = 0; i < dataCount; i++)
    {
        dataFile >> Aval[i] >> Amin[i] >> Bval[i] >> Bmin[i];
    }
    dataFile.close();
}

int FindTimeInMinutesFromInterval(int fromHour, int fromMinute, int toHour, int toMinute)
{
    return abs(toHour - fromHour) * 60 + abs(toMinute - fromMinute);
}

std::string ConvertTimeToHours(int totalMinutes)
{
    int hours = totalMinutes / 60;
    int minutes = totalMinutes % 60;

    return std::to_string(hours) + " val. " + std::to_string(minutes) + " min.";
}

int WriteToResultFile(int timeTotal)
{
    std::ofstream resultFile("result.txt");
    resultFile << ConvertTimeToHours(timeTotal);
    resultFile.close();
}

int main()
{
    ReadFromDataFile();

    int totalTimeInMinutes = 0;
    for (int i = 0; i < dataCount; i++)
    {
        totalTimeInMinutes += FindTimeInMinutesFromInterval(Aval[i], Amin[i], Bval[i], Bmin[i]);
    }

    WriteToResultFile(totalTimeInMinutes);
}