/** * Author: Xan * Date: 24th April 2018. * * Fraction manager: currently allows these: * - adding * - subtracting * - multiplying * - dividing * - inverting (e.g. 5 / 4 ==> 4 / 5) * - simplifying (e.g. 5 / 10 ==> 1 / 2) * * Helping with this question: * https://www.sololearn.com/Discuss/1236987/how-can-i-write-a-c-program-that-will-be-able-to-add-fractions */ #include using namespace std; class FractionManager { private: // The current fraction we are working on. int m_NumeratorCurrent; int m_DemonatorCurrent; private: // Recursive function to return gcd of a and b // // Code for this function taken from: // https://www.geeksforgeeks.org/c-program-find-lcm-two-numbers/ int GetLeastCommonMultiple(int a, int b) { // Base case. if (a == b) { return a; } // a is greater. if (a > b) { return GetLeastCommonMultiple(a - b, b); } return GetLeastCommonMultiple(a, b - a); } // Validate a fraction. void ValidateFraction(int numerator, int denominator) { if (denominator == 0 || numerator == 0) { throw invalid_argument("\nWARNING: Fractions must not have zero as a numerator or denominator.\n"); return; } } public: // Constructor. FractionManager() { m_NumeratorCurrent = 0; m_DemonatorCurrent = 0; } // Simplify the fraction. // e.g. 5 / 10 ==> 1 / 2 void SimplifyFraction() { if (m_NumeratorCurrent != 0 && m_DemonatorCurrent != 0) { int lcm = GetLeastCommonMultiple(m_NumeratorCurrent, m_DemonatorCurrent); m_NumeratorCurrent = m_NumeratorCurrent / lcm; m_DemonatorCurrent = m_DemonatorCurrent / lcm; } } // Is this an improper fraction. // 2 / 3 is proper. 4 / 4 is considered improper, as is 5 / 4. bool IsImproper() { return !IsProper(); } // Is this a proper fraction? // 2 / 3 is proper. 4 / 4 is considered improper, as is 5 / 4. bool IsProper() { return m_NumeratorCurrent < m_DemonatorCurrent; } // A mixed fraction is where instead of display 4 / 3, // we would say 1 & 1 / 3. // // We display an improper fraction as mixed, otherwise // we just display the fraction as it is. void DisplayMixedFraction() { if (IsProper()) { cout << endl << m_NumeratorCurrent << " / " << m_DemonatorCurrent << endl; } else { cout << endl << m_NumeratorCurrent / m_DemonatorCurrent << " & " << m_NumeratorCurrent % m_DemonatorCurrent << " / " << m_DemonatorCurrent << endl; } } // Swap the numerator with the denominator. // e.g. 5 / 4 ==> 4 / 5 void InvertFraction() { int tempNumeratorCurrent = m_NumeratorCurrent; m_NumeratorCurrent = m_DemonatorCurrent; m_DemonatorCurrent = tempNumeratorCurrent; } // Multiply this fraction. void MultiplyFraction(int numerator, int denominator) { ValidateFraction(numerator, denominator); m_NumeratorCurrent *= numerator; m_DemonatorCurrent *= denominator; SimplifyFraction(); } // Divide by this fraction. void DivideFraction(int numerator, int denominator) { // To divide we just invert the fraction, and multiply with it. MultiplyFraction(denominator, numerator); } // Subtract this fraction. void SubtractFraction(int numerator, int denominator) { // To subtract, we just make the numerator (or denominator) // negative, and just add it. AddFraction(-numerator, denominator); } // Add this fraction. void AddFraction(int numerator, int denominator) { ValidateFraction(numerator, denominator); if (m_NumeratorCurrent == 0 && m_DemonatorCurrent == 0) { m_NumeratorCurrent = numerator; m_DemonatorCurrent = denominator; return; } else { // Add the fractions together (making sure we have a common denominator for both fractions). int tempDenominator = denominator * m_DemonatorCurrent; int tempNumerator = (denominator * m_NumeratorCurrent) + (m_DemonatorCurrent * numerator); m_DemonatorCurrent = tempDenominator; m_NumeratorCurrent = tempNumerator; SimplifyFraction(); } } void OutputFractionSoFar() { cout << endl << "==> Fraction So Far: " << m_NumeratorCurrent << " / " << m_DemonatorCurrent << endl << endl; } }; int main() { FractionManager* fractionManager = new FractionManager; try { // Add 2 / 4. cout << endl << "Add 2 / 4" << endl; fractionManager->AddFraction(2, 4); fractionManager->OutputFractionSoFar(); // Multiply 2 / 3. cout << endl << "Multiply 2 / 3" << endl; fractionManager->MultiplyFraction(2, 3); fractionManager->OutputFractionSoFar(); // Add 1 / 6. cout << endl << "Add 1 / 6" << endl; fractionManager->AddFraction(1, 6); fractionManager->OutputFractionSoFar(); // Divide 1 / 4. cout << endl << "Divide 1 / 4" << endl; fractionManager->DivideFraction(1, 4); fractionManager->OutputFractionSoFar(); // Subtract 3 / 4. cout << endl << "Subtract 3 / 4" << endl; fractionManager->SubtractFraction(3, 4); fractionManager->OutputFractionSoFar(); // Display as a mixed fraction (e.g. 5 / 4 displays as 1 & 1 / 4). cout << endl << "Display as a mixed fraction" << endl; fractionManager->DisplayMixedFraction(); cout << endl; // Invert the fraction (e.g. 5 / 4 would become 4 / 5). cout << endl << "Invert the fraction" << endl; fractionManager->InvertFraction(); fractionManager->OutputFractionSoFar(); } catch (const std::invalid_argument& e) { cout << e.what(); } // Delete the fraction manager. delete fractionManager; fractionManager = NULL; return 0; }

Fraction Manager (Add + Subtract + Multiply + Divide + Invert + Simplify)