How to use boolean datatype in C?

Question

I was just writing code in C and it turns out it doesn't have a boolean/bool datatype. Is there any C library which I can include to give me the ability to return a boolean/bool datatype?

Answer 1

If you have a compiler that supports C99 you can

#include <stdbool.h>

Otherwise, you can define your own if you'd like. Depending on how you want to use it (and whether you want to be able to compile your code as C++), your implementation could be as simple as:

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

In my opinion, though, you may as well just use int and use zero to mean false and nonzero to mean true. That's how it's usually done in C.

Answer 2

C99 has a boolean datatype, actually, but if you must use older versions, just define a type:

typedef enum {false=0, true=1} bool;

Answer 3

C99 has a bool type. To use it,

#include <stdbool.h>

Answer 4

As an alternative to James McNellis answer, I always try to use enumeration for the bool type instead of macros: typedef enum bool {false=0; true=1;} bool;. It is safer b/c it lets the compiler do type checking and eliminates macro expansion races

Answer 5

C99 introduced _Bool as intrinsic pure boolean type. No #includes needed:

int main(void)
{
  _Bool b = 1;
  b = 0;
}

On a true C99 (or higher) compliant C compiler the above code should compile perfectly fine.

Answer 6

We can use enum type for this.We don't require a library. For example

           enum {false,true};

the value for false will be 0 and the value for true will be 1.

Answer 7

struct Bool {
    int true;
    int false;
}

int main() {

    /* bool is a variable of data type – bool*/
    struct Bool bool;

    /*below I’m accessing struct members through variable –bool*/ 
    bool = {1,0};
    print("Student Name is: %s", bool.true);
    return 0;
}