[C++知识库]给出日期求是一年的第几天-C语言实现

思路：利用Switch没有braek的下滑的特性完成计算

#include <stdio.h>
int main(){
int sum=0;
int month,day,year;
scanf("%d%d%d",&year,&month,&day);
switch(month){
?? ?case 12:
?? ??? ?sum+=30;
?? ?case 11:
?? ??? ?sum+=31;
?? ?case 10:
?? ??? ?sum+=30;
?? ?case 9:
?? ??? ?sum+=31;
?? ?case 8:
?? ??? ?sum+=31;
?? ?case 7:
?? ??? ?sum+=30;
?? ?case 6:
?? ??? ?sum+=31;
?? ?case 5:
?? ??? ?sum+=30;
?? ?case 4:
?? ??? ?sum+=31;
?? ?case 3:
?? ??? ?sum+=28;
?? ?case 2:
?? ??? ?sum+=31;
?? ?case 1:
?? ??? ?sum+=0;
}
if(month>=3&&year%4==0&&year%400!=0){
?? ?sum+=1;
}
sum+=day;
printf("%d",sum);
return 0;?
}