Repeating Number Array

Question

I am having trouble creating a program that takes in numbers in an Array and returns them by a string. My following code in my

main.m file:

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

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NumberRepeater *repeater1 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@1, @10]]];

        [repeater1 initWithNumbers:@[@[@1, @10]]];
        NSLog(@"%@", [repeater1 process]);

        NumberRepeater *repeater2 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@1, @2], @[@2, @3]]];

        NSLog(@"%@", [repeater2 process]);

        NumberRepeater *repeater3 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@10, @4], @[@34, @6], @[@92, @2]]];

        NSLog(@"%@", [repeater3 process]);
    }
    return 0;
}

The code in my NumberRepeater.h file:

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface NumberRepeater : NSObject
- (instancetype)initWithNumbers:(NSArray *)numbers;

- (NSString *)process;


@end

NS_ASSUME_NONNULL_END

The code in my NumberRepeater.m file:

#import <Foundation/Foundation.h>
#import "NumberRepeater.h"
@implementation NumberRepeater

- (instancetype)initWithNumbers:(NSArray *)numbers {
    NumberRepeater *repeater1 = [[NumberRepeater alloc] 
initWithNumbers: @[@[@1, @10]]];
    [repeater1 initWithNumbers:@[@[@1, @10]]];
    NSLog(@"%@", repeater1);

    return 0;
}

- (NSString *)process {


    return 0;
}

@end

My expected output should be:

1111111111
11, 222
10101010, 343434343434, 9292

This is in no way a school assignment I need solving. I would love a solution however guidance to that would be great. I feel like I almost have it as I have done questions similar to this and have got the output I need but clearly I am missing, I just don't know what. I understand my process method is missing code, it's just I don't exactly know what to put in there. Any help would be greatly appreciated!

Answer 1

• I need to Explain Array syntax for you according to your question ,

1. First you can declare array in this way @[@1,@2,....] this array of NSNumber object as Int Value , because array contain id objects only so we can't user Int directly but we user NSnumber like that @1

2. objects inside array can be Array its self so we can declare array of array object like this example @[@[@10, @4], @[@3, @6], @[@2, @9]] this array of array @[@[],@[],....etc]

• according to your question i I give you NSArray with two items just give me back a String with first item repeated (second item) times

   Example :

        Input @[@1,@2]      repeat number#1  two times
        Output should be 11

        Input @[@1,@10]      repeat number#1  10 times
        Output should be 1111111111

       Input @[@[@1,@3],@[@3,@4]]      repeat number#1  3 times , number#3   4 time
        Output should be 111 3333

Solution

NumberRepeater.h

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface NumberRepeater : NSObject {
      NSArray * numbers; // private number array will be initialized during initialization of object
}
- (instancetype)initWithNumbers:(NSArray *)numbers;

- (NSString *)process;
@end

NS_ASSUME_NONNULL_END

NumberRepeater.m

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


// NumberRepeater Extention for set private numbers
@interface NumberRepeater ()
@property (nonatomic,retain) NSArray *numbers;
@end


@implementation NumberRepeater
@synthesize numbers;

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

    self = [super init];
    if (self) {
        self.numbers = numbers;
    }
    return self;
}

- (NSString *)process {

// if numbers have No Data
   if (numbers.count == 0) { return  @"0"; }

    // Array of array  each array have two element first is number to repeat and second have number of repetation
    // Example @[@1, @2]   repeat number(1)   TWO times  so out put should be 11
 //   @[@[@1, @2], @[@2, @3]]

    NSMutableString * output = [NSMutableString new];

    for (NSArray*item in numbers) {

        // Array should be with this Format
          // Example @[@1, @2]   repeat number(1)   TWO times

              // assert item have tow items only  like that @[@1,@2]
           NSAssert(item.count == 2,@"Array Should have Two items only");

        NSNumber *numberToRepeat = item[0]; // repeat
        NSNumber *repetitionCount = item[1]; //repetition Count

        NSMutableString * repeatdString = [NSMutableString new];

        for (NSInteger i= 0; i < [repetitionCount integerValue] ; i++) {
            [repeatdString appendString:[numberToRepeat stringValue]];
        }

        [output appendString:repeatdString];
        [output appendFormat:@" "]; // space on join with muti array

    }


    return output;
}
@end

main.m

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

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NumberRepeater *repeater1 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@1, @10]]];

        NSLog(@"%@", [repeater1 process]);

        NumberRepeater *repeater2 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@1, @2], @[@2, @3]]];

        NSLog(@"%@", [repeater2 process]);

        NumberRepeater *repeater3 = [[NumberRepeater alloc] 
        initWithNumbers: @[@[@10, @4], @[@34, @6], @[@92, @2]]];

        NSLog(@"%@", [repeater3 process]);
    }
    return 0;
}