Objective-C - How to get sum of Boleans?

问题:

Through the code below, I can get an output such as :
0
1
1

What I want is to output the sum of these booleans values, in my case the result will be :
2 because we have 0+1+1

The code [Update] :

  -(void)markers{         CLLocationCoordinate2D tg = CLLocationCoordinate2DMake(location.latitude, location.longitude);         GMSCoordinateBounds *test = [[GMSCoordinateBounds alloc]initWithPath:path];         BOOL test3 = [test containsCoordinate:tg];         {             if (test3 == 1)             {   marker.position = CLLocationCoordinate2DMake(location.latitude, location.longitude);                                  }else if (test3 == 0)             {   marker.position = CLLocationCoordinate2DMake(0, 0);             }         }     }        } 

回答1:

Rather than sum BOOLs, which is counterintuitive, loop over whatever you are using to get the BOOL values, and if you get YES, increment a counter. This will be the number of YESs that you have.

If you have an array of BOOLs, you could just filter the array with a predicate to get the YES values and the length of the resulting array is the number of YESs that you have.

Edited to add code samples following OP comments

Incrementing a counter

NSUInteger numberOfBools = 0; CLLocationCoordinate2D tg = CLLocationCoordinate2DMake(location.latitude, location.longitude); GMSCoordinateBounds *test = [[GMSCoordinateBounds alloc]initWithPath:path]; if ([test containsCoordinate:tg1]) { ++numberOfBools; } if ([test containsCoordinate:tg2]) { ++numberOfBools: } ... // other tests here;  // numberOfBools now contains the number of passing tests. 

Edited Again, after the full code was added

// snipped code above here // This is where you add the counter and initialise it to 0 NSUInteger numberOfBools = 0; for (NSDictionary *dictionary in array) {                 // Snip more code to this point     BOOL test3 = [test containsCoordinate:tg];     {         if (test3)         {         // This is where you increment the counter         ++numberOfBools;  // Snip more code to the end of the for block }  // Now numberOfBools shows how many things passed test3 

回答2:

int sum = (test3 ? 1 : 0) + (testX ? 1 : 0) + (testY ? 1 : 0); 

And not so weird variant:

#define BOOL_TO_INT(val) ((val) ? 1 : 0)  int sum = BOOL_TO_INT(test3) + BOOL_TO_INT(testX) + BOOL_TO_INT(testY); 

回答3:

You can just add BOOLs since bools are just integers. e.g. :

int sum = 0;  CLLocationCoordinate2D tg = CLLocationCoordinate2DMake(location.latitude, location.longitude); GMSCoordinateBounds *test = [[GMSCoordinateBounds alloc]initWithPath:path]; BOOL test3 = [test containsCoordinate:tg]; //Obtain bolean values :  BOOL testX = /* other test */; BOOL testY = /* other test */;  sum = test3 + testX + testY 

This is a bad idea however, as BOOLs aren't necessarily 1 or 0. They are 0 and not 0

BOOL is just a typedef-ed char: typedef signed char BOOL; YES and NO are 1 and 0, but BOOL variable = 2 is perfectly valid

For example:

- (int) testX {     if(inState1) return 1;     if(inState2) return 2;      else return 0; }  BOOL textXResult = [self testX]; //Might return 2, this is still equivalent to YES. 

The best solution is to iterate your BOOLs and instead count the number of YESes.

回答4:

Another way to do this is to assume that if any one value is false, then the entire array is false, so, loop over the array until a false value is found, then break:

BOOL retval = true;  //return holder variable  /*'boolsNumArray' is an NSArray of NSNumber instances, converted from BOOLs:      //BOOL-to-NSNumber conversion (makes 'boolsNumArray' NSArray, below)!     '[myNSArray addObject:[NSNumber numberWithBool:yourNextBOOL]]'   */ for(NSNumber* nextNum in boolsNumArray) {     if([nextNum boolValue] == false) {         retval = false;         break;     } }  return retval; 

文章来源: Objective-C - How to get sum of Boleans?