我们可以用四种方法检查

第一种方法是

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

第二种方法是

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

第三种方法是

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

第四种方法是

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);

布尔值只是整数，它们只是类型转换的值，比如……

typedef signed char     BOOL; 

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

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

如果输出为1，则为YES，否则为NO

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

注意，在Swift中，你可以这样做

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

这将记录testBool = true

我是这样做的:

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

?:是三元条件运算符，形式为:

condition ? result_if_true : result_if_false

在适当的地方替换实际的日志字符串。

直接将bool值打印为整数

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

- > curBool = 0

将bool类型转换为字符串

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

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

- > curBool =虚假