错误描述

unknown type name ‘bool’

最近使用C实现数据结构碰到了以下这个错误

➜  LinkedList gcc list.c 
list.c:14:1: error: unknown type name ‘bool’; did you mean ‘_Bool’?
 bool is_empty(PNODE pHead);
 ^~~~
 _Bool
list.c:77:1: error: unknown type name ‘bool’; did you mean ‘_Bool’?
 bool is_empty(PNODE pHead)
 ^~~~
 _Bool
list.c: In function ‘is_empty’:
list.c:80:9: error: ‘true’ undeclared (first use in this function); did you mean ‘free’?
  return true;
         ^~~~
         free
list.c:80:9: note: each undeclared identifier is reported only once for each function it appears in
list.c:82:9: error: ‘false’ undeclared (first use in this function); did you mean ‘fclose’?
  return false;
         ^~~~~

错误原因

未知的类型名：‘bool’, 因为在C语言标准(C89)没有定义布尔类型，所以会报错。而C99提供了一个头文件<stdbool.h>定义了bool，true代表1，false代表0。只要导入stdbool.h，就能非常方便的操作布尔类型了。

解决方法

#include <stdbool.h>

参考链接

https://www.jianshu.com/p/aa951e784e96