Where is the bowl type defined in C?

In C, there is no bool type, so you have to define and write it yourself. I'll introduce three things that are commonly used

typedef int bool;
#define true 1
#define false 0

typedef int bool;
enum { false, true };

typedef enum { false, true } bool;

#include <stdbool.h>

Choose any of these Personally, I don't like 4 because it can only be used in C99 I think 2 and 3 are better because they don't use #define.