main.m

//
//  main.m
//  ReindeerGamesObjC
//
//  Created by Paul Wilkinson on 9/02/2016.
//  Copyright © 2016 Paul Wilkinson. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Reindeer.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Reindeer *comet=[[Reindeer alloc] initWithSpeed:14 endurance:10 restTime:127];
        Reindeer *dancer=[[Reindeer alloc] initWithSpeed:16 endurance:11 restTime:162];
        
        int time=2503;
        
        int cometDistance=[comet distanceOverTime:time];
        int dancerDistance=[dancer distanceOverTime:time];
        
        NSString *winner=@"Dancer";
        
        if (cometDistance > dancerDistance) {
            winner=@"Comet";
        } else if (cometDistance==dancerDistance) {
            winner=@"dead heat";
        }
        
        NSLog(@"After %d seconds, Comet distance=%dkm, Dancer distance=%dkm. The winner was: %@",time,cometDistance,dancerDistance,winner);
        
    }
    return 0;
}

Reindeer.h

//
//  Reindeer.h
//  ReindeerGamesObjC
//
//  Created by Paul Wilkinson on 9/02/2016.
//  Copyright © 2016 Paul Wilkinson. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Reindeer : NSObject

@property int endurance;
@property int speed;
@property int restTime;

-(id)initWithSpeed:(int)speed endurance:(int)endurance restTime:(int)restTime;

-(int)distanceOverTime:(int)duration;


@end

Reindeer.m

//
//  Reindeer.m
//  ReindeerGamesObjC
//
//  Created by Paul Wilkinson on 9/02/2016.
//  Copyright © 2016 Paul Wilkinson. All rights reserved.
//

#import "Reindeer.h"

@implementation Reindeer

-(id)initWithSpeed:(int)speed endurance:(int)endurance restTime:(int)restTime {
    if (self=[super init]) {
        self.speed=speed;
        self.endurance=endurance;
        self.restTime=restTime;
    }
    return self;
}

-(int) distanceOverTime:(int)duration {
    int phase=0;
    int distanceTravelled=0;
    
    for (int i=1;i<duration;i++){
        if (phase < self.endurance) {
            distanceTravelled+=self.speed;
        } else if (phase > self.restTime+self.endurance) {
            phase = -1;
        }
        phase++;
    }
    
    return distanceTravelled;
    
    
}

@end