如何修改这个编程中的错误

#include<stdio.h>
    void date(int year,int month,int day);
    int main()
    {
        int year,month,day;
        printf("请输入年月日:");
        scanf("%d,%d,%d",&year,&month,&day);
        date(year,month,day);
        return 0;
    }
    void date(int year,int month,int day)
    {
         int month_new[12],sum,i;

         if((month<1||month>12)||((month==2)&&(day>29))||(day<1||day>31))
         {
            printf("数据错误!请重新运行程序.\n");
            //scanf("%d,%d,%d",&year,&month,&day);
            
         }
         else
         {
            //设置本年各月份天数.
            for(i=0;i<12;i++)
            {
                if((i==1)&&((year%4==0&&year%100!=0)||(year%400==0)))
                {
                    month_new[i]=29;
                }
                else if(i==1)
                {
                     month_new[i]=28;
                }
                else if(i==0||i==2||i==4||i==6||i==7||i==9||i==11)
                {
                     month_new[i]=31;
                }
                else
                {
                     month_new[i]=30;
                }
           }
           //进行天数的计算
           for(i=0,sum=0;i<month-1;i++)
           {
               sum+=month_new[i];               
           }
           sum=sum+day;
           printf("%d月%d日是%d年的第 %d 天 \n",month,day,year,sum);
   
         }
    }