struct date
{
    int year;
    int month;
    int day;
};
void main()
{
    void cf(struct date *p);
    struct date s1,*p;
    printf("请输入今天的日期:  ");
    scanf("%d %d %d",&s1.year,&s1.month,&s1.day);
    p=&s1;
    cf(p);
}
void  cf(struct date *p)
{   
    struct date s2;
    if(p->day<28)
        s2.year=p->year;
        s2.month=p->month;
        s2.day=p->day+1;
    else if(p->day==28)
         if(p->year%4==0&&p->year%100!=0||p->year%400==0)
           s2.year=p->year;
           s2.month=p->month;
           s2.day=p->day+1;
         else
             s2.year=p->year;
             if(p->month==2)
               s2.month=3;
               s2.day=1;
             else
               s2.month=p->month;
               s2.day=p->day+1;
     else if(p->day==29)
         if(p->year%4==0&&p->year%100!=0||p->year%400==0)
             if(p->month==2)
               s2.month=3;
               s2.day=1;
             else
               s2.year=p->year;
               s2.month=p->month;
               s2.day=p->day+1;
    else if(p->day==30)
        if(p->month==1||3||5||7||8||10||12)
           s2.year=p->year;
           s2.month=p->month;
           s2.day=p->day+1;
        else
           s2.year=p->year;
           s2.month=p->month+1;
           s2.day=1;
    else
        if(p->month==12)
            s2.year=p->year+1;
        else
           s2.year=p->year;
           s2.month=p->month+1;
           s2.day=1;
    printf("输出新的日期:%d %d %d\n",s2.year,s2.month,s2.day);
}







            


 

是啊，不知怎么简化

printf scanf运行为undeclared identifier，标准库函数，怎么会成为未定义标识符

struct date
{
    int year;
    int month;
    int day;
};
void main()
{
    void cf(struct date *p);
    struct date s1,*p;
    printf("请输入今天的日期:  ");
    scanf("%d %d %d",&s1.year,&s1.month,&s1.day);
    p=&s1;
    cf(p);
}
void  cf(struct date *p)
{   
    struct date s2;
    if(p->day<28)
    {
        s2.year=p->year;
        s2.month=p->month;
        s2.day=p->day+1;
    }
    else if(p->day==28)
    {
         if(p->year%4==0&&p->year%100!=0||p->year%400==0)
         {
           s2.year=p->year;
           s2.month=p->month;
           s2.day=p->day+1;
         }
         else
             s2.year=p->year;
             if(p->month==2)
             {
               s2.month=3;
               s2.day=1;
             }
             else
             {
               s2.month=p->month;
               s2.day=p->day+1;
             }
    }
    else if(p->day==29)
         if(p->year%4==0&&p->year%100!=0||p->year%400==0)
             if(p->month==2)
             {
               s2.year=p->year;
               s2.month=3;
               s2.day=1;
             }
             else
             {
               s2.year=p->year;
               s2.month=p->month;
               s2.day=p->day+1;
             }
         else
         {
            s2.year=p->year;
            s2.month=p->month;
            s2.day=p->day+1;
         }
    else if(p->day==30)
        if(p->month==1||3||5||7||8||10||12)
        {
           s2.year=p->year;
           s2.month=p->month;
           s2.day=p->day+1;
        }
        else
        {
           s2.year=p->year;
           s2.month=p->month+1;
           s2.day=1;
        }
    else
        if(p->month==12)
        {
            s2.year=p->year+1;
            s2.month=1;
            s2.day=1;
        }
        else
        {
           s2.year=p->year;
           s2.month=p->month+1;
           s2.day=1;
        }
    printf("输出新的日期:%d年%d月%d日\n",s2.year,s2.month,s2.day);
}

发现问题了，原来＃include<stdio.h>没有引用

不过五楼的设计思想更科学，值得学习！！

if(p->month==1||3||5||7||8||10||12)
这样表述行吗，大侠指点