How to print Boolean flag in NSLog?

Here's how I do it:

BOOL flag = YES;
NSLog(flag ? @"Yes" : @"No");

?: is the ternary conditional operator of the form:

condition ? result_if_true : result_if_false

Substitute actual log strings accordingly where appropriate.

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%d, 0 is FALSE, 1 is TRUE.

BOOL b; 
NSLog(@"Bool value: %d",b);

or

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

On the bases of data type %@ changes as follows

For Strings you use %@
For int  you use %i
For float and double you use %f

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Booleans are nothing but integers only, they are just type casted values like...

typedef signed char     BOOL; 

#define YES (BOOL)1
#define NO (BOOL)0

BOOL value = YES; 
NSLog(@"Bool value: %d",value);

If output is 1,YES otherwise NO

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Note that in Swift, you can just do

let testBool: Bool = true
NSLog("testBool = %@", testBool.description)

This will log testBool = true

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While this is not a direct answer to Devang's question I believe that the below macro can be very helpful to people looking to log BOOLs. This will log out the value of the bool as well as automatically labeling it with the name of the variable.

#define LogBool(BOOLVARIABLE) NSLog(@"%s: %@",#BOOLVARIABLE, BOOLVARIABLE ? @"YES" : @"NO" )

BOOL success = NO;
LogBool(success); // Prints out 'success: NO' to the console

success = YES;
LogBool(success); // Prints out 'success: YES' to the console

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Apple's FixIt supplied %hhd, which correctly gave me the value of my BOOL.

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We can check by Four ways

The first way is

BOOL flagWayOne = TRUE; 
NSLog(@"The flagWayOne result is - %@",flagWayOne ? @"TRUE":@"FALSE");

The second way is

BOOL flagWayTwo = YES; 
NSLog(@"The flagWayTwo result is - %@",flagWayTwo ? @"YES":@"NO");

The third way is

BOOL flagWayThree = 1;
NSLog(@"The flagWayThree result is - %d",flagWayThree ? 1:0);

The fourth way is

BOOL flagWayFour = FALSE; // You can set YES or NO here.Because TRUE = YES,FALSE = NO and also 1 is equal to YES,TRUE and 0 is equal to FALSE,NO whatever you want set here.
NSLog(@"The flagWayFour result is - %s",flagWayFour ? YES:NO);

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NSArray *array1 = [NSArray arrayWithObjects:@"todd1", @"todd2", @"todd3", nil];
bool objectMembership = [array1 containsObject:@"todd1"];
NSLog(@"%d",objectMembership);  // prints 1 or 0

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Here is how you can do it:

BOOL flag = NO;
NSLog(flag ? @"YES" : @"NO");

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In Swift, you can simply print a boolean value and it will be displayed as true or false.

let flag = true
print(flag) //true

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//assuming b is BOOL. ternary operator helps us in any language.
NSLog(@"result is :%@",((b==YES)?@"YES":@"NO"));

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Direct print bool to integer

BOOL curBool = FALSE;
NSLog(@"curBool=%d", curBool);

-> curBool=0

Convert bool to string

char* boolToStr(bool curBool){
    return curBool ? "True": "False";
}

BOOL curBool = FALSE;
NSLog(@"curBool=%s", boolToStr(curBool));

-> curBool=False

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