Solution

// Katrina Ward 3/8/2019

// File: fractions.cpp CS1570

// Description: A single file program for Moe to add and divide fractions.

#include <iostream>

using namespace std;

// Function Prototypes

// Function: greeting()

// Description: Displays a greeting to the screen

// Pre: None

// Post: Will output a message to the screen

void greeting();

// Function: goodbyes()

// Description: Will display an exit greeting to the screen

// Pre: None

// Post: Will display a message to the screen.

void goodbyes();

// Function: menu()

// Description: Displays a menu to the user and returns their menu choice

// Pre: None

// Post: Outputs a message to the screen

char menu();

// Function: noFracError()

// Description: Displays an error message to the screen that the user

// has not entered any fractions yet

// Pre: None

// Post: Outputs a message to the screen

void noFracError();

// Function: getFrac()

// Description: Prompts for and reads in the numerator and denominator

// for a fraction

// Pre: None

// Post: The numerator and denominator will be changed to read in values

void getFrac(int & num, int & den);

// Function: addFrac()

// Description: Adds two fractions together and passes the answer back

// Pre: Neither denominators of te two added fractions can be 0

// Post: Will change the values of the third fraction passed to be the

// sum of the first two fractions

void addFrac(const int firstNum, const int firstDen, const int secondNum,

const int secondDen, int & ansNum, int & ansDen);

// Function: divideFrac()

// Description: Divides two fractions and passes back the answer

// Pre: Neither denominators of the two divided fractions can be 0

// Post: Will change the values of the third fraction passed to be the

// answer of the first two fractions divided

void divideFrac(const int firstNum, const int firstDen, const int secondNum,

const int secondDen, int & ansNum, int & ansDen);

// Fraction: displayFrac()

// Description: Displays a fraction to the screen

// Pre: None

// Post: Will display the passed fraction to the screen.

void displayFrac(const int num, const int den);

// Function: simplifyFrac()

// Description: Simplifies a function

// Pre: None

// Post: Will change the function passed to the simplified version

void simplifyFrac(int & num, int & den);

int main()

{

char choice; // User choice from menu

bool quit = false; // Flag to quit program

bool enterFrac = false // Flag to mark the first option was chosen

int num1, den1, num2, den2; // Entered fraction variables

int ansNum, ansDen; // Answer from the arithmetic functions

greeting();

do{

choice = menu();

switch(choice)

{

case '1': case 'e': case 'E':

getFrac(num1, den1);

getFrac(num2, den2);

enterFrac = true;

break;

case '2': case 'a': case 'A':

if(!enterFrac) // Check if fractions were entered first

noFracError();

else

{

addFrac(num1, den1, num2, den2, ansNum, ansDen);

simplifyFrac(ansNum, ansDen);

displayFrac(ansNum, ansDen);

}

break;

case '3': case 'd': case 'D':

if(!enterFrac)

noFracError();

else

{

divideFrac(num1, den1, num2, den2, ansNum, ansDen);

simplifyFrac(ansNum, ansDen);

displayFrac(ansNum, ansDen);

}

break;

case '4': case 's': case 'S':

if(!enterFrac)

noFracError();

else

{

simplifyFrac(num1, den1);

simplifyFrac(num2, den2);

cout <<"For the first fraction, ";

displayFrac(num1, den1);

cout <<"For the second fraction, ";

displayFrac(num2, den2);

}

break;

case '5': case 'q': case 'Q':

goodbyes();

quit = true;

break;

default:

cout << "Invalid menu choice. Please enter a number from the menu.\n";

}

} while(!quit);

return 0;

}

void greeting()

{

cout << "Welcome to the fractionator!" << endl;

return;

}

void goodbyes()

{

cout << "Thank you for using the fractionator! You're a genius now!" << endl;

return;

}

char menu()

{

char choice;

cout << "\t\tMenu" << endl;

cout << "\n1. Enter Fractions" << endl;

cout << "2. Add Fractions" << endl;

cout << "3. Divide Fractions" << endl;

cout << "4. Display Simplified Fractions" << endl;

cout << "5. Quit" << endl;

cout << "Enter your selection: ";

cin >> choice;

return choice;

}

void noFracError()

{

cout << "You have to enter fractions before they can be added!\n";

return;

}

void getFrac(int & num, int & den)

{

cout << "Input a numerator: ";

cin >> num;

cout << "\nInput a denominator: ";

cin >> den;

while(den==0) // Prevents a fractions entered with a 0 denominator

{

cout << "The denominator cannot be zero!\nChoose a different denominator: ";

cin >> den;

}

// Make a fraction with a negative numerator and denominator positive

// If only the denominator is negative, moves the negative to the

// numerator for cleaner arithmetic later.

if((num<0 && den < 0) || den < 0)

{

num *= -1;

den *= -1;

}

return;

}

void addFrac(const int firstNum, const int firstDen, const int secondNum,

const int secondDen, int & ansNum, int & ansDen)

{

ansDen = firstDen * secondDen;

ansNum = (firstNum*secondDen) + (secondNum*firstDen);

return;

}

void displayFrac(const int num, const int den)

{

cout << "Your fraction is: " << num;

// Will just display 0 if the numerator is 0 for cleaner output.

if(num!=0)

cout << "/" << den << endl;

else

cout << endl;

return;

}

void simplifyFrac(int & num, int & den)

{

for(int i=num*den; i > 0; i--)

{

if((den % i == 0) && (num % i == 0))

{

den/=i;

num/=i;

}

}

return;

}

void divideFrac(const int firstNum, const int firstDen, const int secondNum,

const int secondDen, int & ansNum, int & ansDen)

{

ansNum = firstNum * secondDen;

ansDen = firstDen * secondNum;

return;

}