[数据结构与算法]2021-10-03

c语言练习题：输入年月份输出天数是这一年中的第几天

#include <stdio.h>//输入年月十分判断这是这一年的第几天
int main(int argc, char const *argv[])
{
    int sum=0;
    int year=0,mon=0,day=0;
    int mon2=0;
    printf("欢迎来到本系统\n");
    printf("请输入年月份（格式为空格）");
    scanf("%d %d %d",&year,&mon,&day);
    if(year<0){
        printf("输入错误请重新输入");
    }
    if((year%100!=0&&year%4==0)||year%400==0){
        mon2=29;
    }else{
        mon2=28;
    }
    switch (mon)
    {
    case 1:sum+=day;break;
    case 2:sum+=(31+day);break;
    case 3:sum+=(31+mon2+day);break;
    case 4:sum+=(31+mon2+31+day);break;
    case 5:sum+=(31+mon2+31+30+day);break;
    case 6:sum+=(31+mon2+31+30+31+day);break;
    case 7:sum+=(31+mon2+31+30+31+30+day);break;
    case 8:sum+=(31+mon2+31+30+31+30+31+day);break;
    case 9:sum+=(31+mon2+31+30+31+30+31+31+day);break;
    case 10:sum+=(31+mon2+31+30+31+30+31+31+30+day);break;
    case 11:sum+=(31+mon2+31+30+31+30+31+31+30+31+day);break;
    case 12:sum+=(31+mon2+31+30+31+30+31+31+30+31+30+day);break;
    
    default:
    printf("你输入错误请重新输入\n");
        break;
    }
       if(mon==1||mon==3||mon==5||mon==7||mon==8||mon==10||mon==12){
        day<=31&&day>0;
        if(day>31||day<0){
            printf("输入错请重新输入\n");
        }else{
            printf("%d %d %d是这一年中的第%d天\n",year,mon,day,sum);
        }
    }else if(mon==4||mon==6||mon==9||mon==11){
        day<=30&&day<0;
        if(day>30||day<0){
            printf("输入错误请重新输入\n");
        }else{
            printf("%d %d %d是这一年中的第%d天\n",year,mon,day,sum);
        }
    }
     if(mon==2){
     if((year%100!=0&&year%4==0)||year%400==0){
        day<=29&&day!=0;
        if(day<=29&&day>0){
        printf("%d %d %d是这一年中的第%d天\n",year,mon,day,sum);
        }else{
            printf("%d是平年，请重新输入\n",year);
        }
    }else{
        day<=28&&day!=0;
        if( day<=28&&day>0){
        printf("%d %d %d是这一年中的第%d天\n",year,mon,day,sum);
        }else{
            printf("%d是平年请重新输入\n",year);
        }
    }
    }
        
    return 0;
}