undefined reference to 'winmain @16'

struct date
{
int month;
int day;
int year;
};
struct person
{
char name[10];
struct date birthday;
long certificate;
};

你没有写main函数

undefined reference to winmain @16' winmain @ 16定义的参考 undefined reference to winmain @16' winmain @ 16定义的参考