Converting a date to dayOfWeek

Here is the full code in C

#include "stdio.h"

typedef enum DayOfWeek_ {SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY} DayOfWeek;

// month is 1 to 12
int getDayOfWeek(int year, int month, int dayOfMonth)
{
    int m[12] = {4, 0, 0, 3, 5, 1, 3, 6,2, 4, 0, 2};
    int dayOfWeek = ((year-1) * 5 / 4 - 5) + m[month-1] + dayOfMonth;
    int leap = 0;   
    
    if(year % 4 == 0) {
        leap = 1;
        if(year % 100 == 0) {
            leap = 0;
            if(year % 400 == 0) {
                leap = 1;
            }
        }
    }
    if(leap && month >= 3)
        dayOfWeek++;

    return (dayOfWeek % 7);
}   

char *getDayOfWeekName(int dayOfWeek)
{
    switch(dayOfWeek) {
        case 0: return "SUNDAY";
        case 1: return "MONDAY";
        case 2: return "TUEDAY";
        case 3: return "WEDNESDAY";
        case 4: return "THURSDAY";
        case 5: return "FRIDAY";
        case 6: return "SATURDAY";
    }
    //
    return "ERROR";
}

int main()
{
    printf("dayOfWeek(2000, 3, 17)=%s\n", getDayOfWeekName(getDayOfWeek(2000, 3, 17)));
    printf("dayOfWeek(2000, 1, 15)=%s\n", getDayOfWeekName(getDayOfWeek(2000, 1, 15)));   
    printf("dayOfWeek(2010, 3, 17)=%s\n", getDayOfWeekName(getDayOfWeek(2010, 3, 17)));

    return 0;
}

Enjoy