Programming training 7- date conversion problem

Test description
According to the following function prototype, use function programming to solve the following date conversion problem （ Ask to consider leap years ）：
Enter the date of the year , Calculate and output the day of the year .
/* The functionality ： For a given year, month and day , Calculate and return the day of the year it is
Function parameter ： Integer variables year、month、day, Each represents the year 、 month 、 Japan
Function return value ： The day of the year */
int DayofYear(int year, int month, int day);
Input
Input 3 It's an integer , Each represents the year 、 month 、 Japan , Use a space between two adjacent items .
Output
Output an integer , It means the day of the year .
Input example
2000 1 31
Output example
31

#include <stdio.h>
int DayofYear(int year, int month, int day)
{
	int i,leap,n=0,a[12]={31,28,31,30,31,30,31,31,30,31,30,31};
	leap=(year%4==0&&year%100!=0)||year%400==0;		
	for(i=0;i<month-1;i++)										
		n=n+a[i];
	if(month>2)											
		n=n+leap;
	return n+day;
}

int main()
{

	int n,year,month,day;
	
	scanf("%d%d%d",&year,&month,&day);	
	n=DayofYear(year,month,day);								
	
  	printf("%d",n);							
	return 0;