用结构体制作书籍表问题
为什么结果会多输出一个[书籍编号:] ?#include <stdio.h>
#include <stdlib.h>
struct Book
{
char name;
char author;
struct Book *next;
};
void Input(struct Book *book);
void Input(struct Book *book)
{
printf("请输入书名\n");
scanf("%s", book->name);
printf("请输入书作者\n");
scanf("%s", book->author);
}
void addbook(struct Book **lib);
void addbook(struct Book **lib)
{
struct Book *book, *temp;
book = (struct Book *)malloc(sizeof(struct Book));
Input(book);
if(*lib != NULL)
{
temp = *lib;
*lib = book;
book->next = temp;
}
else
{
*lib = book;
book->next = NULL;
}
}
void printlib(struct Book *book);
void printlib(struct Book *book)
{
int count = 1;
while(book != NULL)
{
printf("书籍编号:%d\n", count);
printf("书籍名称:%s\n", book->name);
printf("书籍作者:%s\n", book->author);
book = book->next;
count++;
}
}
void releaselib(struct Book *book);
void releaselib(struct Book *book)
{
struct Book *temp;
while(book != NULL)
{
temp = book->next;
free(book);
book = temp;
}
}
int main()
{
struct Book *lib;
int ch;
while(1)
{
printf("请问是否需要录入书籍信息(Y/N):\n");
do
{
ch = getchar();
}
while(ch != 'Y' && ch != 'N');
if(ch == 'Y')
addbook(&lib);
else
break;
}
printf("请问是否需要打印图书信息(Y/N):");
do
{
ch = getchar();
}
while(ch != 'Y' && ch != 'N');
if(ch == 'Y')
{
printlib(lib);
}
releaselib(lib);
return 0;
} int main()
{
struct Book *lib = NULL;//将lib初始化为NULL
int ch;
如果不初始化为NULL，addBook第一本书时 if(*lib != NULL) 条件即成立。
addBook后尾节点的next是一个未知值(应该是NULL才对)，printlib循环到最后时：
printf("书籍编号:%d\n", count);
printf("书籍名称:%s\n", book->name);//这行访问的是一个未知地址的name，所以出错。
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