Problem with Exercise 13.4(ARC)

[Anatoliy Gatt]

Hi guys!
I'm stuck on the Exercise 13.4

So here is the code:
Function

Code: (Objective-C)

Fraction *calculateFractions (Fraction  **array, int numberOfElements) {
    Fraction *resultFraction = [[Fraction alloc] initWithNumerator:0 andDenominator:1];
    Fraction *holder;
    
    for(int i = 1; i < numberOfElements; i++) {
        holder = [resultFraction add:array[i]];
        resultFraction = holder;
    }
    
    return resultFraction;
}

Code in main

Code: (Objective-C)

const int numberOfFractions = 5;
        
        Fraction *fractionArrayElementOne = [[Fraction alloc] initWithNumerator:5 andDenominator:10];
        Fraction *fractionArrayElementTwo = [[Fraction alloc] initWithNumerator:8 andDenominator:13];
        Fraction *fractionArrayElementThree = [[Fraction alloc] initWithNumerator:7 andDenominator:15];
        Fraction *fractionArrayElementFour = [[Fraction alloc] initWithNumerator:9 andDenominator:23];
        Fraction *fractionArrayElementFive = [[Fraction alloc] initWithNumerator:4 andDenominator:17];
        
        Fraction __autoreleasing *arrayOfFractions[numberOfFractions]= {fractionArrayElementOne, fractionArrayElementTwo, fractionArrayElementThree, fractionArrayElementFour, fractionArrayElementFive};
        
        printf("Fraction Expression: %i/%i + %i/%i + %i/%i + %i/%i + %i/%i = ", arrayOfFractions[0].numerator, arrayOfFractions[0].denominator, arrayOfFractions[1].numerator, arrayOfFractions[1].denominator, arrayOfFractions[2].numerator, arrayOfFractions[2].denominator, arrayOfFractions[3].numerator, arrayOfFractions[3].denominator, arrayOfFractions[4].numerator, arrayOfFractions[4].denominator);
        
        Fraction *calculateFractions (Fraction **array, int numberOfElements);
        
        Fraction *resultOfFractionArrayCalculation = calculateFractions(arrayOfFractions, 5);
        
        printf("%i/%i\n", resultOfFractionArrayCalculation.numerator, resultOfFractionArrayCalculation.denominator);

Output
Fraction Expression: 5/10 + 8/13 + 7/15 + 9/23 + 4/17 = 1/0

What is the problem?
Why it is 1/0?

Thanks in advance!!!

[Anatoliy Gatt]

Would I get any help?