#include<stdio.h> void month_day(int year,int days,int *month,int *day){ int d[2][13] = { {0,31,28,31,30,31,30,31,31,30,31,30,31}, {0,31,29,31,30,31,30,31,31,30,31,30,31} }; int sum = 0,isRun; if((year % 4 == 0 && year % 100 != 0) || year % 400 == 0){ isRun = 1; } else{ isRun = 0; } for(int i=0;i<13;i++){ sum+=d[isRun][i]; if(sum>days){ *month = i-1; *day = days-sum+d[isRun][i]; printf("%d,%d",*month,*day); break; } } } int main(){ int *month,*day; month = day = NULL; int year,days; printf("请输入年份：\n"); scanf("%d",&year); printf("请输入天数：\n"); scanf("%d",&days); month_day(year,days,month,day); printf("今天日期是：%d:%d:%d",year,*month,*day); return 0; }这段代码哪里出错了

这段代码中出现了指针未初始化的问题，导致程序出错。具体来说，`month`和`day`指针未指向任何有效的内存地址，使用它们进行赋值操作会导致程序崩溃。为了解决这个问题，可以将`month`和`day`声明为普通的整型变量，并传入函数中进行赋值操作，如下所示：

#include<stdio.h> 

void month_day(int year,int days,int *month,int *day){ 
    int d[2][13] = { {0,31,28,31,30,31,30,31,31,30,31,30,31}, {0,31,29,31,30,31,30,31,31,30,31,30,31} }; 
    int sum = 0,isRun; 
    if((year % 4 == 0 && year % 100 != 0) || year % 400 == 0){ isRun = 1; } 
    else{ isRun = 0; } 
    for(int i=0;i<13;i++){ 
        sum+=d[isRun][i]; 
        if(sum>days){ 
            *month = i-1; 
            *day = days-sum+d[isRun][i]; 
            printf("%d,%d",*month,*day); 
            break; 
        } 
    } 
} 

int main(){ 
    int month,day; // 修改这里
    int year,days; 
    printf("请输入年份：\n"); 
    scanf("%d",&year); 
    printf("请输入天数：\n"); 
    scanf("%d",&days); 
    month_day(year,days,&month,&day); // 修改这里
    printf("今天日期是：%d:%d:%d",year,month,day); 
    return 0; 
}

另外，程序中还存在一处小问题，`printf("%d,%d",*month,*day)`后面应该加上换行符`\n`，否则输出结果会与后面的日期信息连在一起。