Codeee

#import "AppDelegate.h"
#import "binarySearch.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    binarySearch *objSearch = [[binarySearch alloc] init];

    NSArray *array = [NSArray arrayWithObjects: @1, @2, @3, @4, @5, @6, @7, @8, nil];

    [objSearch initWithArray:array];
    [objSearch searchFor: 6];
@end


#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface binarySearch : NSObject

//properties
@property (strong, nonatomic) NSArray *list;
@property (assign, nonatomic) NSInteger middle;

//functions
-(instancetype) initWithArray: (NSArray*) array;
-(NSInteger) searchFor: (NSInteger) number;

@end

NS_ASSUME_NONNULL_END


#import "binarySearch.h"

@implementation binarySearch

-(instancetype) initWithArray:(NSArray *)array {
    NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 integerValue] > [obj2 integerValue];
    }];

    if (![array isEqualToArray:sortedArray]) {
        NSLog(@"okeys");
        return nil;

    }

    if (self = [super init]) {
        self.list = array;
        self.middle = array.count / 2;
    }
    NSLog(@"initArray!");
    return self;

}

-(NSInteger) searchFor:(NSInteger)number {
    NSInteger middle = self.list.count / 2;
    NSInteger middleValue = [self.list[middle] integerValue];
    NSArray *subarray = self.list;
    do {
        if (number == middleValue) {
            NSLog(@"%d", [self.list indexOfObject:subarray[middle]]);
            return [self.list indexOfObject:subarray[middle]];

        }
        if (middle == 0) {

            NSLog(@"not found!");
            return NSNotFound;

        }
        if (number > middleValue) {
            subarray = [subarray subarrayWithRange:NSMakeRange(middle + 1, subarray.count % 2 == 0 ? middle - 1 : middle)];
        } else {
            subarray = [subarray subarrayWithRange:NSMakeRange(0, middle)];
        }
        middle = subarray.count / 2;
        middleValue = [subarray[middle] integerValue];
    } while (YES);

    return NSNotFound;
}


@end