Adding numbers in an Array with a given condition

Question

I have numbers in an array, odd and even, I have to add the odd ones with one another and the even ones wit one another. I am very confused as to how to go about this because of the parameters and conditions given:

In my Adder.h file I have the following:

@interface ConditionalAdder : NSObject

- (instancetype)initWithNumbers:(NSArray *)numbers;

- (int)sumWithCondition:(NSString *)condition;

@end

In my Main.m file I have the following code:

#import "ConditionalAdder.h"

int main(int argc, const char * argv[]) {
  @autoreleasepool {

ConditionalAdder *adder1 = [[ConditionalAdder alloc] 
initWithNumbers:@[@1, @2, @3, @4, @5]];
NSLog(@"%i", [adder1 sumWithCondition:@"even"]);
NSLog(@"%i", [adder1 sumWithCondition:@"odd"]);

ConditionalAdder *adder2 = [[ConditionalAdder alloc] 
initWithNumbers:@[@13, @88, @12, @44, @99]];
NSLog(@"%i", [adder2 sumWithCondition:@"even"]);

ConditionalAdder *adder3 = [[ConditionalAdder alloc] 
initWithNumbers:@[]];
NSLog(@"%i", [adder3 sumWithCondition:@"odd"]);
  } 

return 0;
}

I know that this method:

- (int)sumWithCondition:(NSString *)condition;

Should return an integer, but what string am I supposed to pass through the parameter?

Jeshua Lacock · Accepted Answer · 2018-12-30 02:47:46Z

1

You didn't show your sumWithCondition function. But you can utilize the mod operation which is %. Mod will return 0 if the first number is wholly divisible by the second number.

This should work (assuming your number array is called numbers)

NSArray *numbers;

- (int)sumWithCondition:(NSString *)condition {

    int sum = 0;
    int modCondition = 0;

    if ([condition isEqualToString:@"odd"]) {
        modCondition = 1; //Set Mod condition to odd
    }
    else {
        modCondition = 0; //Set Mod condition to even
    }

    for (int i = 0; i < [numbers count]; i++){ //Iterate over each value in array
        int thisValue = [[numbers objectAtIndex:i] intValue];

        if ((thisValue % 2) == modCondition) { //If value is odd or even depending on condition
            sum += thisValue; //Then add value to sum
        }

    }

    return sum;
}

edited Dec 30, 2018 at 2:47

answered Dec 30, 2018 at 1:44

Jeshua Lacock

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1 Comment

OmieiOS Over a year ago

Hi Jeshua, sorry never mind, it did! My mistake. Thank you!

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