Arithmetic Operations on Factions

FractionArithmetic.cpp

#include <iostream>
using namespace std;

enum MenuSelectionEnum
{
  	MENU_NONE = 0,
	MENU_ADD = 1,
	MENU_SUBTRACT = 2,
	MENU_MULTIPLY = 3,
	MENU_DIVIDE = 4,
	MENU_QUIT = 5,
	MENU_END = 6
};

int menu();
void addFractions(int num1, int num2, int den1, int den2, int&resultNum, int&resultDen);
void subtractFractions(int num1, int num2, int den1, int den2, int&resultNum, int&resultDen);
void multiplyFractions(int num1, int num2, int den1, int den2, int&resultNum, int&resultDen);
void divideFractions(int num1, int num2, int den1, int den2, int&resultNum, int&resultDen);
void outputResults(int num1, int num2, int den1, int den2, int resultNum, int resultDen, int operation);
void inputFractionValuesFromUser(int &num1, int &num2, int &den1, int &den2);
void reduceFraction(int &resultNum, int &resultDen);


void main()
{
	int menuSelect = MENU_NONE;
	int num1 = 0, num2 = 0, den1 = 0, den2 = 0;
	int resultNum = 0, resultDen = 0;
	
	
	menuSelect = menu();
	inputFractionValuesFromUser(num1, num2, den1, den2);
		
	if (menuSelect == MENU_ADD)
	{
		addFractions(num1, num2, den1, den2, resultNum, resultDen);
	}
		
	if (menuSelect == MENU_SUBTRACT)
	{
		subtractFractions(num1, num2, den1, den2, resultNum, resultDen);
	}
		
	if (menuSelect == MENU_MULTIPLY)
	{
		multiplyFractions(num1, num2, den1, den2, resultNum, resultDen);
	}
		
	if (menuSelect == MENU_DIVIDE)
	{
		divideFractions(num1, num2, den1, den2, resultNum, resultDen);
	}
		
	outputResults(num1, num2, den1, den2, resultNum, resultDen, menuSelect);
		
	system("PAUSE");
	
} // end main

int menu()
{
	int menuItemSelect = 0;
	
	do
	{
		cout << "Fraction Calculator" << endl;
		cout << "1. Add Fractions " << endl;
		cout << "2. Subtract Fractions " << endl;
		cout << "3. Multiply Fractions " << endl;
		cout << "4. Divide Fractions " << endl;
		cout << "5. Quit" << endl;
		cout << "Please make a selection: " << endl;
		cin >> menuItemSelect;
		if(menuItemSelect <= MENU_NONE || menuItemSelect >= MENU_END)
			cout << "Invalid selection! " << endl;
	}
	while(menuItemSelect <= MENU_NONE || menuItemSelect >= MENU_END);
	
	return menuItemSelect;
}

// first four for input, second two for output
void addFractions( int num1, int num2, int den1, int den2, int &resultNum, int &resultDen)
{
	// not using sturctures because I don't know them -- no local values because
	// the outside world wouldn't know  & symbols pass by value for resultNum and resultDen
	resultNum = (num1 * den2) + (num2 * den1);
	resultDen = den1 * den2;
}
		
void subtractFractions( int num1, int num2, int den1, int den2, int&resultNum, int &resultDen)
{
	resultNum = (num1 * den2) - (num2 * den1);
	resultDen = den1 * den2;
}

void multiplyFractions(int num1, int num2, int den1, int den2, int &resultNum, int &resultDen)
{
	resultNum = num1 * num2;
	resultDen = den1 * den2;
}

void divideFractions(int num1, int num2, int den1, int den2, int &resultNum, int &resultDen)
{
	resultNum = num1 * den2;
	resultDen = den1 * num2;
}

void outputResults(int num1, int num2, int den1, int den2, int resultNum, int resultDen, int operation)
{
	// could all be switch here!!
	if(operation == MENU_ADD)
	{
		reduceFraction(resultNum, resultDen);
		cout << num1 << '/' << den1 << " + " << num2 << '/' << den2 << " = " << resultNum << '/' << resultDen << endl;
	}
	
	if(operation == MENU_SUBTRACT)
	{
		reduceFraction(resultNum, resultDen);
		cout << num1 << '/' << den1 << " - " << num2 << '/' << den2 << " = " << resultNum << '/' << resultDen << endl;	
	}
	
	if(operation == MENU_MULTIPLY)
	{
		reduceFraction(resultNum, resultDen);
		cout << num1 << '/' << den1 << " * " << num2 << '/' << den2 << " = " << resultNum << '/' << resultDen << endl;
	}
	
	if(operation == MENU_DIVIDE)
	{
		reduceFraction(resultNum, resultDen);
		cout << num1 << '/' << den1 << " / " << num2 << '/' << den2 << " = " << resultNum << '/' << resultDen << endl;
	}
}

void inputFractionValuesFromUser(int &num1, int&num2, int &den1, int &den2)
{
	cout << endl;
	cout << "Please enter first fraction numerator: ";
	cin >> num1;
	cout << "Please enter first fraction denominator: ";
	cin >> den1;
	cout << endl;
	cout << "Please enter second fraction numerator: ";
	cin >> num2;
	cout << "Please enter second fraction denominator: ";
	cin >> den2;
}

void reduceFraction(int &resultNum, int &resultDen)
{
        for (int i = resultDen * resultNum; i > 1; i--) 
	{  
			if ((resultDen % i == 0) && (resultNum % i == 0)) 
			{  
				resultDen /= i;  
                		resultNum /= i;  
			}  
                  
        }
}