#import <Foundation/Foundation.h>
#import <math.h>

const int MAX_RAND_NUMBER = 100;
const int SIZE = 50;

NSNumber * makeRandomNumber()
{
    return [[NSNumber alloc] initWithFloat:(random() % MAX_RAND_NUMBER) + 1];
}

NSDictionary * makeDictionary(int capacity)
{
    NSMutableDictionary * out = [[NSMutableDictionary alloc] initWithCapacity:capacity];
    srandom(time(NULL));
    for (int i = 0; i < capacity; i++) {
        [out setValue:makeRandomNumber() forKey:[NSString stringWithFormat:@"%i", i]];
    }
    return out;
}


@interface NSDictionary (Statictics)

-(float)averageArit;
-(float)averageGeo;
-(float)averageHarm;
-(float)median;
-(float)centralMoment:(unsigned int)k;
-(float) variance;
-(float) standardDeviation;
-(float) coefficientOfVariation;
-(float) skewness;
-(float) kurtosis;
-(float) variationsRange;

@end


@implementation NSDictionary (Statictics)

-(float)averageArit
{
    float sum = 0.0;
    for(NSString * item in self) {
        sum += [[self valueForKey:item] floatValue];
    }
    if ([self count]) {
        return sum/(float)[self count];
    } else {
        return sum;
    }
}

-(float) averageGeo
{
    long double mul = 1;
    for (NSString * item in self) {
        NSNumber * val = [self valueForKey:item];
        mul *= [val doubleValue];
    }

    if ([self count] && mul) {
        return (float)(powl(mul, 1.0/(float)[self count]));
    } else {
        return 0.0;
    }
}

-(float) averageHarm
{
    long double mul = 1;
    for (NSString * item in self) {
        NSNumber * val = [self valueForKey:item];
        mul += 1.0/[val floatValue];

    }

    if ([self count] && mul) {
        return (float)[self count] / mul;
    } else {
        return 0;
    }

}

-(float) median
{
    NSArray * sorted = [[self allObjects] sortedArrayUsingSelector:@selector(compare:)];
    int arrSize = [sorted count];
    if (arrSize%2 == 1) {
        return [[sorted objectAtIndex:arrSize/2] floatValue];
    } else {
        return [[sorted objectAtIndex:arrSize/2] floatValue] + [[sorted objectAtIndex:arrSize/2 + 1] floatValue] / 2.0;
    }
}

-(float) centralMoment:(unsigned int)k
{
    float medianValue = [self median];
    long double count = 0;
    for (NSString * item in self) {
        double val = [[self valueForKey:item] doubleValue];
        count += powl(medianValue - val, k);
    }
    if ([self count]) {
        return count/(float)[self count];
    } else {
        return 0.0;
    }
}

-(float) variance
{
    return [self centralMoment:2.0];
}

-(float) standardDeviation
{
    return powf([self variance], 0.5);
}


-(float) coefficientOfVariation
{
    return [self standardDeviation] / fabs([self median]);
}

-(float) skewness
{
    return [self centralMoment:3.0] / powf([self standardDeviation], 3.0);
}

-(float) kurtosis
{
    return [self centralMoment:4.0] / powf([self standardDeviation], 4.0) - 3.0;
}

-(float) variationsRange
{
    return [[self valueForKeyPath:@"@max"] floatValue] - [[self valueForKeyPath:@"@min"] floatValue];
}

@end



int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSDictionary * dict = [[NSDictionary alloc] initWithDictionary:makeDictionary(SIZE)];

    //NSLog(@"%@", dict);
    float averageArithm = [dict averageArit];
    NSLog(@"Aritmeticky prumer: %f", averageArithm);
    NSLog(@"Geometricky prumer: %f", [dict averageGeo]);
    NSLog(@"Harmonicky prumer: %f", [dict averageHarm]);
    NSLog(@"Median: %f", [dict median]);
    NSLog(@"Rozptyl: %f", [dict variance]);
    NSLog(@"Smerodatna odchylka: %f", [dict standardDeviation]);
    NSLog(@"Variacni koeficient: %f", [dict coefficientOfVariation]);
    NSLog(@"Koeficient sikmosti: %f", [dict skewness]);
    NSLog(@"Koeficient spicatosti: %f", [dict kurtosis]);
    //NSLog(@"Variacni rozpeti: %f", [dict variationsRange]);

    [pool drain];
    return 0;
}