sex输出要用%c
结构体要写在main函数外面
例如:
#include <stdio.h>
struct Books
{
char title[50];
char author[50];
char subject[100];
int book_id;
} book = {"C 语言", "RUNOOB", "编程语言", 123456};
int main()
{
printf("title : %s\nauthor: %s\nsubject: %s\nbook_id: %d\n", book.title, book.author, book.subject, book.book_id);
}