Encode NMEA GGA and ZDA messages using C++

cpp_encode_nmea_gga_zda.cpp

#include <iostream>
#include <sstream>
#include <iomanip>

using namespace std;

char computeChecksum(const std::string& str)
{
    char checksum = 0;
    for (int i=0; i<str.size(); ++i)
    {
        checksum ^= str[i];
    }
    return checksum;
}

std::string zda(
    int hour=3,
    int minute=40,
    float second=4.6,
    int day=1,
    int month=8,
    int year=2000,
    int local_hours=+1, // -13 .. 13
    int local_minutes=0 // 0..59
)
{
    std::stringstream stream;
    stream 
        << "$--ZDA,"
        << std::fixed
        << std::setbase(10)
        << std::setfill('0')
        << std::setw(2)
        << hour
        << minute
        << std::setw(5)
        << std::setprecision(2)
        << second
        << ","
        << std::setw(2)
        << day
        << ","
        << std::setw(2)
        << month
        << ","
        << std::setw(4)
        << year
        << ","
        << std::setw(2)
        << local_hours
        << ","
        << std::setw(2)
        << local_minutes
        << "*"
    ;
    std::string str = stream.str();
    stream 
        << std::setw(2) 
        << std::setbase(16)
        << static_cast<int>(computeChecksum(str))
        << "\r\n"
    ;
    return stream.str();
}

std::string gga(
    int hour=3,
    int minute=40,
    float second=4.6,
    float latitude=52.1,
    float longitude=11.6,
    int gpsQualityIndicator=1, // 0: fix_not_available, 1: gps fix, 2: dgps fix
    int numSats=10,
    float hdop=5,
    float altitude=0,
    char altitudeUnit = 'M',
    float geoidalSeparation=0,
    char geoidalSeparationUnit = 'M',
    float dgpsAge=0,
    int dgpsReferenceStationId=0    
)
{
    char NorS = (latitude >= 0) ? 'N' : 'S';
    char EorW = (longitude >= 0) ? 'E' : 'W';

    std::stringstream stream;
    stream 
        << "$--GGA,"
        << std::fixed
        << std::setbase(10)
        << std::setfill('0')
        << std::setw(2)
        << hour
        << minute
        << std::setw(5)
        << std::setprecision(2)
        << second
        << ","
        << std::setw(7)
        << std::setprecision(2)
        << abs(latitude)
        << ","
        << NorS
        << ","
        << std::setw(7)
        << std::setprecision(2)
        << abs(longitude)
        << ","
        << EorW
        << ","
        << std::setw(1)
        << gpsQualityIndicator
        << ","
        << std::setw(2)
        << numSats
        << ","
        << std::setw(3)
        << std::setprecision(1)
        << hdop
        << ","
        << std::setw(3)
        << std::setprecision(1)
        << altitude
        << ","
        << altitudeUnit
        << ","
        << std::setw(3)
        << std::setprecision(1)
        << geoidalSeparation
        << ","
        << geoidalSeparationUnit
        << ","
        << std::setw(3)
        << std::setprecision(1)
        << dgpsAge
        << ","
        << std::setw(4)
        << dgpsReferenceStationId
        << "*"
    ;
    std::string str = stream.str();
    stream 
        << std::setw(2) 
        << std::setbase(16)
        << static_cast<int>(computeChecksum(str))
        << "\r\n"
    ;
    return stream.str();
}

int main() {
    std::cout << gga();
    std::cout << zda();
    // $--GGA,034004.60,0052.10,N,0011.60,E,1,10,5.0,0.0,M,0.0,M,0.0,0000*5a
    // $--ZDA,034004.60,01,08,2000,01,00*70
}