计算当日是该年的第几天---C语言

#include<stdio.h>

typedef struct{
    int year;
    int month;
    int day;
}info; 

int main()
{
    int i,cot = 0;
    info mes;
    scanf("%d%d%d",&mes.year,&mes.month,&mes.day);

    //存放每个月的天数 
    int m[12] = {31,28,31,30,31,30,31,31,30,31,30,30};
    //闰年时2月有29天 
    if(mes.year%4==0&&mes.year%100!=0||mes.year%400==0)
        m[1] = 29;
        
    for(i=0;i<mes.month-1;i++)
        cot += m[i];
    cot += mes.day;

    printf("%d",cot);
    
    return 0;
}