How to find leap year programmatically in C

I wrote a program in C to find whether the entered year is a leap year or not. But unfortunately its not working well. It says a year is leap and the preceding year is not leap.

#include <stdio.h>
#include <conio.h>

int yearr(int year);

void main(void) {
    int year;
    printf("Enter a year:");
    scanf("%d", &year);
    if (!yearr(year)) {
        printf("It is a leap year.");
    } else {
        printf("It is not a leap year");
    }

    getch();
}

int yearr(int year) {
    if ((year % 4 == 0) && (year / 4 != 0))
        return 1;
    else
        return 0;
}

After reading the comments I edited my code as:

#include <stdio.h>
#include <conio.h>

int yearr(int year);

void main(void) {
    int year;
    printf("Enter a year:");
    scanf("%d", &year);
    if (!yearr(year)) {
        printf("It is a leap year.");
    } else {
        printf("It is not a leap year");
    }

    getch();
}

int yearr(int year) {
    if (year % 4 == 0) {
        if (year % 400 == 0)
            return 1;
        if (year % 100 == 0)
            return 0; 
    } else
        return 0;
}

Your logic to determine a leap year is wrong. This should get you started (from Wikipedia):

if year modulo 400 is 0
       then is_leap_year
else if year modulo 100 is 0
       then not_leap_year
else if year modulo 4 is 0
       then is_leap_year
else
       not_leap_year

x modulo y means the remainder of x divided by y. For example, 12 modulo 5 is 2.