bool for function in c language

Question

I would like to use bool in c language

first I see in C++

int maximum(int state, **bool choose**);

then

new_state = maximum(now_State, **true**);

I use boolean in C language by this:

#define true 1 
#define false 0 

typedef int boolean; 
boolean choose = false ;

but I dont know how to set on function like this(C++).

int maximum(int state, **bool choose**);

new_state = maximum(now_State, **true**);

Im foreigner. If you dont understand please tell me.

Both C++ and C have a built-in bool type. For C it's called _Bool but if you #include <stdbool.h> then you can use bool. — Simple
– Simple, Commented Dec 17, 2013 at 10:55
"but I dont know how to set on function like this(C++)." - I don't understand this. What do you mean by "set on function"? — user529758
– user529758, Commented Dec 17, 2013 at 11:00
for example int maximum(int state, bool choose); bool dont have in C language. So, int maximum(int state, xxxxxx); How I change. — Supaphon Kamon
– Supaphon Kamon, Commented Dec 17, 2013 at 11:04

haccks · Accepted Answer · 2013-12-17 10:56:50Z

6

To use Boolean type C99 provides <stdbool.h> header. This header provides a macro bool. This header also contains the header true and false which stand for 1 and 0 respectively.

answered Dec 17, 2013 at 10:56

haccks

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7 Comments

doynax Over a year ago

More to the point it is a proper boolean type. So something along the lines of bool k = 2; if(k == true) will work as expected

Elias Van Ootegem Over a year ago

@doynax: well, true is a macro that expands to 1, and false expands to 0, so defining typedef int bool and #define true 1 isn't that different

Angew is no longer proud of SO Over a year ago

@EliasVanOotegem Except that the code which donyax shows wouldn't work with typedef int bool.

Elias Van Ootegem Over a year ago

@SupaphonKamon: That's because microsoft didn't support C99. That should've changed with VS2013, though

user694733 Over a year ago

It is best to always test booleans as if(k) or if(!k) anyway, as it makes porting easier.

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Oleg Razgulyaev · Accepted Answer · 2013-12-17 11:05:00Z

2

I would recommend to use enum:

#include <stdio.h>

typedef enum { false, true } bool;

int main() {
    bool x = false;
    if(x != true)
        printf("x=%d\n",x);
}

answered Dec 17, 2013 at 11:05

Oleg Razgulyaev

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