Parse GPS String for Time and Coordinates

#include <stdio.h>
#include <string.h>

void parse_gprmc(char *nmea)
{
    char field[12][20];
    int idx = 0, j = 0;

    for (int i = 0; nmea[i] != '\0' && idx < 12; ++i)
    {
        if (nmea[i] == ',')
        {
            field[idx][j] = '\0';
            idx++;
            j = 0;
        }
        else
        {
            if (j < 19)
                field[idx][j++] = nmea[i];
        }
    }

    field[idx][j] = '\0';


    char *t = field[1];

    printf("Time: %.2s:%.2s:%.2s\n", t, t+2, t+4);
    printf("Latitude: %s %s\n", field[3], field[4]);
    printf("Longitude: %s %s\n", field[5], field[6]);
}

int main() {
    char nmea[100];
    fgets(nmea, sizeof(nmea), stdin);
    parse_gprmc(nmea);
    return 0;
}