在函数中传递结构

Passing structure in a function

以下代码在编译时出错:

int add_employee(struct emp e)
     {
        printf("%i\n", e.emp_no);
        printf("Date of Birth:\n");
        printf("%i / %i / %i\n", e.birth_date.dd, e.birth_date.mm, e.birth_date.yyyy);
        printf("%s %s\n", e.first_name, e.last_name);
        printf("%s\n", e.gender);
        printf("Date of Hirting:\n");
        printf("%i / %i / %i\n", e.hire_date.dd, e.hire_date.mm, e.hire_date.yyyy);
        return 0;
    }

    int main()
    {
        struct employees emp, *ptr;
        ptr = &emp;
        int i=0;
        ptr->emp_no = get_int("Employee No.: ");
        printf("Date of Birth:\n");
        ptr->birth_date.dd = get_int("Date: ");
        ptr->birth_date.mm = get_int("Month: ");
        ptr->birth_date.yyyy = get_int("Year: ");
        ptr->first_name = get_string("First Name: ");
        ptr->last_name = get_string("Last Name: ");
        ptr->gender = get_string("Gender(M/F): ");
       printf("Date of Hiring:\n");
       ptr->hire_date.dd = get_int("Date: ");
       ptr->hire_date.mm = get_int("Month: ");
       ptr->hire_date.yyyy = get_int("Year: ");
      i = add_employee(emp);
       if(i == 0)
       {
           printf("Employee added successfully\n");
       }

下面是我用clang编译时的错误:

app.c:75:25: warning: declaration of 'struct emp' will not be visible outside of this function [-Wvisibility]
int add_employee(struct emp e)
                        ^
app.c:75:29: error: variable has incomplete type 'struct emp'
int add_employee(struct emp e)
                            ^
app.c:75:25: note: forward declaration of 'struct emp'
int add_employee(struct emp e)
                        ^
app.c:104:22: error: argument type 'struct emp' is incomplete
    i = add_employee(emp);
                     ^~~
app.c:75:25: note: forward declaration of 'struct emp'
int add_employee(struct emp e)
                        ^
1 warning and 2 errors generated.

查看 main

中的行
struct employees emp, *ptr;

类型好像是struct employees.

所以函数应该是

int add_employee(struct employees e)