Objective-C formatting string for boolean?

What formatter is used for boolean values?

EDIT:


Example: ` NSLog(@" ??", BOOL_VAL);`, what is `??` ?

One way to do it is to convert to strings (since there are only two possibilities, it isn't hard):

NSLog(@" %s", BOOL_VAL ? "true" : "false");

I don't think there is a format specifier for boolean values.

I would recommend

NSLog(@"%@", boolValue ? @"YES" : @"NO");

because, um, `BOOL`s are called `YES` or `NO` in Objective-C.

Format strings for use with NSLog and [NSString stringWithFormat] are documented here:

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BOOL/bool/boolean are not even mentioned...

In Objective-C, the `BOOL` type is just a signed char. From `<objc/objc.h>`:

typedef signed char BOOL;
#define YES (BOOL)1
#define NO (BOOL)0

So you can print them using the `%d` formatter But that will only print a `1` or a `0`, not `YES` or `NO`.

Or you can just use a string, as suggested in other answers.

Use the integer formatter `%d`, which will print either `0` or `1`:

NSLog(@"%d", myBool);

I created a category of NSString with this

+ (instancetype)stringWithBool:(BOOL)boolValue {
return boolValue ? @"YES" : @"NO";
}

And use it like this:

[NSString stringWithBool:boolValue];

Just add the below function and pass it the `BOOL` value and method will return back the `NSString`

- (NSString *)boolValueToString:(BOOL)theBool {
if (theBool == 0)
return @"NO"; // can change to No, NOOOOO, etc
else
return @"YES"; // can change to YEAH, Yes, YESSSSS etc
}

Add this inline function to your `.h` file:

static inline NSString* NSStringFromBOOL(BOOL aBool) {
return aBool? @"YES" : @"NO";
}

Now you are ready to go...

NSLog(@"%@", NSStringFromBOOL(BOOL_VAL));

I believe the easiest way to do this is:

NSLog(@" %@", @(BOOL_VAL));

> @(expression)

Dynamically evaluates the boxed expression and returns the appropriate object literal based on its value (i.e. NSString for const char*, NSNumber for int, etc.).