#include<stdio.h>
int main()
{
    int fun_(int,int,int);
    printf("请输入年月日！");
    int a,b,c,sum;
    scanf("%d %d %d",&a,&b,&c);
    sum=fun_(a,b,c);
    printf("这一天是这年的第%d天\n",sum);
    return 0;
}

int fun_(int m,int n,int k)
{
    int a[12]={1,2,3,4,5,6,7,8,9,10,11,12},b[12]={31,28,31,30,31,30,31,31,30,31,30,31},c[12]={31,29,31,30,31,30,31,31,30,31,30,31};
    int sum=k,i;
    if((m%4==0&&m%100!=0)||m%400==0)//判断是否为闰年
    for(i=0;i<n-1;i++)
    sum+=c[i];
    else
    for(i=0;i<n-1;i++)
    sum+=b[i];
    return(sum);
}
请各位帮我看看这程序还有什么可以改进的地方，谢谢啦！

#include <stdio.h>

int dayofyear( int year, int month, int day );

int main( void )
{
    int year, month, day;
    printf("请输入年月日: ");
    scanf( "%d%d%d", &year, &month, &day );
    printf( "这一天是这年的第%d天\n", dayofyear(year,month,day) );

    return 0;
}

int dayofyear( int year, int month, int day )
{
    const int a[2][13] = { {0,0,31,59,90,120,151,181,212,243,273,304,334}
                         , {0,0,31,60,91,121,152,182,213,244,274,305,335} };
    return a[year%400==0 || (year%4==0&&year%100!=0)][month] + day;
}