#include    <stdio.h>

main(int argc, char *argv[])
{   char str[3]; int m, n=-3; double year=0.;
    double latd, latf, lond, lonf, alt, f, fm[6];
    opnpinc(argc, argv);
    premsg("\nCalculate IGRF components\n");
    while (n < -2) {
        prompt("Select model - DGRF (d), PGRF (p), IGRF (i),\n");
        gparma("                 or by Generation (1-)   ==> ", 3, &str);
        if ((str[0]=='d') || (str[0]=='D')) n = -2;
        else if ((str[0]=='p') || (str[0]=='P')) n = -1;
        else if ((str[0]=='i') || (str[0]=='I')) n = 0;
        else if ((str[0]>='0') || (str[0]<='9')) {
            m = str[0] - '0';
            if ((m!=0) && ((str[1]=='\0') || (str[1]==' '))) n = m;
            else if ((str[1]>='0') || (str[1]<='9')) n = m*10 + str[1] - '0';
        }
    }
    while (year < 1900.)
        gparmd("Select the YEAR of calculation  ==> ", &year);
    if (n == -2) { sdgrf(year); printf("\nDGRF in %7.2f\n", year); }
    else if (n == -1) { spgrf(year); printf("\nPGRF in %7.2f\n", year); }
    else if (n == 0) { sigrf(year); printf("\nIGRF in %7.2f\n", year); }
    else { gigrf(n, year); printf("\nIGRF-%d in %7.2f\n", n,year); }
    while (1) {
        latd = 99999.; latf = 0.; lond = 0.; lonf = 0.; alt = 0.;
        prompt("\n  Latitude ?  (deg. min.)\n");
        gparmd2("   < Hit RETURN to Quit > ==> ", &latd,&latf);
        if (latd == 99999.) { fputc('\n',stderr); break; }
        gparmd2("  Longitude ? (deg. min.) ==> ", &lond,&lonf);
        gparmd("  Altitude ?  (in meters) ==> ", &alt);
        latd = latd+latf/60.; lond = lond+lonf/60.;
        igrfc(latd, lond, alt, &f); igrfm(fm);
        printf("%7.3f N %8.3f E %6.0f m  :  F =%8.1f  H =%8.3f  Z =%8.3f\n",
                latd, lond, alt, f, fm[3], fm[2]);
        printf("                              dip =%8.3f   dec =%8.3f\n",
                fm[4], fm[5]);
    }
    clspin();
}