C语言实现计算一年中过了多少天

#include <stdio.h>
#include <stdlib.h>


int daysofmonth(int year, int month)
{
switch(month)
{
case 1:
return 31;

case 2:
if(leapornot(year))return 29;
return 28;

case 3:
return 31;


case 4:
return 30;

case 5:
return 31;


case 6:
return 30;


case 7:
return 31;


case 8:
return 31;


case 9:
return 30;


case 10:
return 31;


case 11:
return 30;


case 12:
return 31;


default:
return 0;


}
}


int leapornot(int year)
{
if((year%100 != 0)&&(year%4 == 0)) return 1;
if(year%400 == 0) return 1;
return 0;
}


int sumday(int year, int month, int day)
{
int i = 1;
int sum = 0;

for(i =1; i < month; i++)
{
printf("daysofmonth = %d\n", daysofmonth(year, i));
sum += daysofmonth(year, i);  //注意：此处必定不要把i写成month。
}

sum += day;

return sum;
}




int main()
{
int sumd;

sumd = sumday(2017, 5, 27);

printf("sum day = %d\n", sumd);

}

输出打印：

daysofmonth = 31
daysofmonth = 28
daysofmonth = 31
daysofmonth = 30
sum day = 147