NSNumber Extensions

NSNumber+NSNumberExtensions.h

//
//  NSInteger+NSIntegerExtensions.h
//  IntegerFunctions
//
//  Created by Geoff Armstrong on 10/30/15.
//  Copyright © 2015 Geoff Armstrong. All rights reserved.
//

#ifndef NSNumber_NSNumberExtensions_h
#define NSNumber_NSNumberExtensions_h

@interface NSNumber (NSIntegerExtensions)

- (NSString *) integerToString;

- (int) countOnesInBinaryInteger;

@end

#endif /* NSInteger_NSIntegerExtensions_h */

NSNumber+NSNumberExtensions.m

//
//  NSInteger+NSIntegerExtensions.m
//  IntegerFunctions
//
//  Created by Geoff Armstrong on 10/30/15.
//  Copyright © 2015 Geoff Armstrong. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "NSNumber+NSNumberExtensions.h"
#define asciiShift 48

@implementation NSNumber (NSIntegerExtensions)

- (NSString *) integerToString {
    BOOL isNegative = NO;
    NSInteger theInteger = [self integerValue];
    NSMutableString *theString = [[NSMutableString alloc] init];
    
    //Check to see if the integer is negative
    if ([self integerValue] < 0) {
        isNegative = YES;
        theInteger *= -1;
    }
    
    //Cycle through the digits of the integer
    while (theInteger > 0) {
        int digit = theInteger % 10;
        unichar character = (unichar) digit + asciiShift;
        [theString insertString:[NSString stringWithCharacters:&character length:1] atIndex:0];
        theInteger /= 10;
    }
    if (isNegative) {
        unichar character = '-';
        [theString insertString:[NSString stringWithCharacters:&character length:1] atIndex:0];
    }
    return theString;
}

- (int) countOnesInBinaryInteger {
    BOOL isNegative = NO;
    int count = 0;
    NSInteger theInteger = [self integerValue];
    
    //Check to see if the integer is negative
    if ([self integerValue] < 0) {
        isNegative = YES;
        theInteger *= -1;
    }
    
    while (theInteger > 0) {
        int digit = theInteger % 2;
        if (digit) {
            count++;
        }
        //Bitshift integer to the right (equivalent to divide by 2)
        theInteger >>= 1;
    }
    
    //Add negative bit?
    if (isNegative) {
        count++;
    }
    
    return count;
}

@end