Fraction Class hw assignment

[orangemexican]

I'm supposed to write a class Fraction

2 constructors: Fraction (); and Fraction (int numerator, int denominator);

The second constructor

will reduce the fraction if needed. Section 4.2 has an algorithm for finding the greatest common divisor of two numbers. Use it to write a function GCD;
if the denominator is negative, the constructor will make it positive and make the numerator negative.
the denominator of a fraction should not be 0. If the user passes a 0 denominator, the proper thing to do would be throw an exception, but we have not studied exception handling yet. So for now, we will assume a well-behaved use who will never pass a denominator of 0 to the constructor

this is what i have so far all on main, have not separated into header and function.cpp yet

#include <iostream>
#include <string>

using namespace std;

class Fraction{
public:
	Fraction();
	Fraction(int numerator, int denominator);
	string fractionToString();

	

private:
	int numerator;
	int denominator;
	int a;
	int b;
	int GCD(int a, int b);
	void reduce();
};

int main(int argc, const char * argv[])
{
	return 0;
}

Fraction::Fraction()
{
	numerator = 0;
	denominator = 1;
}

Fraction::Fraction(int a, int b)
{
	numerator = a;
	denominator = b;
}

void Fraction::reduce()
{
	int a, b, r, gcd;
	a = (numerator);
	b = (denominator);
	if (a == 0)
	{
		numerator = 0;
		denominator = 1;
		return;
	}
	while (a != 0)
	if (a<b)
	{
		r = a; a = b; b = r;
		a = a - b;
	}
	int gcd = b;
	numerator = numerator / gcd;
	denominator = denominator / gcd;

}

Fraction::int GCD(int a, int b)
{

}

string Fraction::fractionToString()
{
	return "numerator" to_string(numerator) "/" "denomenator" to_string(denominator);
}

[giblit]

I don't exactly see a question what do you need help with?

Also you did not implement any of this:

The second constructor

will reduce the fraction if needed. Section 4.2 has an algorithm for finding the greatest common divisor of two numbers. Use it to write a function GCD;
if the denominator is negative, the constructor will make it positive and make the numerator negative.

*fixed tags

[orangemexican]

Ok i implemented the GCD section, and i moved some stuff around on the string fraction function.

i know i haven't written anything on the main yet. I tried compiling it and got an error that said, int gcd redefinition on line 56

#include <iostream>
#include <string>

using namespace std;

class Fraction{
public:
	Fraction();
	Fraction(int numerator, int denominator);
	string fractionToString();
	int GCD(int a, int b);


private:
	int numerator;
	int denominator;
	int a;
	int b;
	void reduce();
};

int main(int argc, const char * argv[])
{
	return 0;
}

Fraction::Fraction()
{
	numerator = 0;
	denominator = 1;
}

Fraction::Fraction(int a, int b)
{
	numerator = a;
	denominator = b;
}

void Fraction::reduce()
{
	int a, b, r, gcd;
	a = (numerator);
	b = (denominator);
	if (a == 0)
	{
		numerator = 0;
		denominator = 1;
		return;
	}
	while (a != 0)
	if (a<b)
	{
		r = a; a = b; b = r;
		a = a - b;
	}
	int gcd = b;
	numerator = numerator / gcd;
	denominator = denominator / gcd;

}

int Fraction::GCD(int a, int b)
{
	while (a != b){
		if (b > a){
			b = b - a;
		}
		else { a = a - b; }
	}
	return a, b;
}






string Fraction::fractionToString()
{
	return "numerator"; to_string(numerator); "/"; "denomenator"; to_string(denominator);
}

[giblit]

You already defined gcd on line 41. I don't think you meant to define on line 41.

[orangemexican]

Thanks for your help giblit, ok so i tried writing the main function but when i compile it gives me the word "numerator"

#include <iostream>
#include <string>

using namespace std;

class Fraction{
public:
	Fraction();
	Fraction(int numerator, int denominator);
	string fractionToString();
	int GCD(int a, int b);


private:
	int numerator;
	int denominator;
	int a;
	int b;
	void reduce();
};

int main(int argc, const char * argv[])
{
	Fraction f1(3,7);
	Fraction f2(4,8);

	cout << f1.fractionToString() << endl;
	cout << f1.fractionToString() << endl;

	

	cin.get();
	return 0;
}

Fraction::Fraction()
{
	this->numerator = 0;
	this->denominator = 0;
}

Fraction::Fraction(int a, int b)
{
	this->numerator = a;
	this->denominator = b;
}

void Fraction::reduce()
{
	int a, b, r;
	a = (numerator);
	b = (denominator);
	if (a == 0)
	{
		numerator = 0;
		denominator = 1;
		return;
	}
	while (a != 0)
	if (a<b)
	{
		r = a; a = b; b = r;
		a = a - b;
	}
	int gcd = b;
	numerator = numerator / gcd;
	denominator = denominator / gcd;

}

int Fraction::GCD(int a, int b)
{
	while (a != b){
		if (b > a){
			b = b - a;
		}
		else { a = a - b; }
	}
	return a, b;
}


string Fraction::fractionToString() /*probably because of how i have this set up, but using the ; all those times was the only way i was able to get rid of the error messages haha*/
{
	return "numerator"; to_string(numerator); "/"; "denomenator"; to_string(denominator);
}

[giblit]

return "numerator"; to_string(numerator); "/"; "denomenator"; to_string(denominator);

This returns "numerator." I am not sure what you wish for output but if you want simply numerator/denominator it would be: return to_string(numerator) + "/" + to_string(denominator);

[orangemexican]

ok i'm adding some more to it, plus the instructions:

Write a class Fraction to represent fractions such as 2/3, 5/4. or -3/7.

The class will have two constructors

Fraction(); //set numerator and denominator to 1)
Fraction(int numerator, int denominator);
The second constructor

will reduce the fraction if needed. Section 4.2 has an algorithm for finding the greatest common divisor of two numbers. Use it to write a function GCD;
if the denominator is negative, the constructor will make it positive and make the numerator negative.
the denominator of a fraction should not be 0. If the user passes a 0 denominator, the proper thing to do would be throw an exception, but we have not studied exception handling yet. So for now, we will assume a well-behaved use who will never pass a denominator of 0 to the constructor
Then overload the multiplication and division operators. Addition and subtraction are more complicated and we will leave that for another day

Also implement

int GCD(int a, int b); returns the greatest common divisor of a and b
void reduce(); reduces this fraction to lowest terms
string fractionToString(); returns a string of the form "3/4" if the numerator was 3 and the denominator was 4.
In the main function, create some fractions, multiply and divide them and print the result.

Implement the program as three files - a fraction.h header file, the main.cpp file and a fraction.cpp file. If you have trouble getting three files to work, try writing all in one file so you know the functions work and then separating it into the different files.

#include <iostream>
#include <string>

using namespace std;

class Fraction{
public:
	Fraction();
	Fraction(int numerator, int denominator);
	string fractionToString();
	int GCD(int a, int b);


private:
	int numerator;
	int denominator;
	int a;
	int b;
	void reduce();
};

int main(int argc, const char * argv[])
{
	Fraction f1(3,7);
	Fraction f2(4,8);
	Fraction product;
	Fraction quotient;

	product = f1*f2;
	
	quotient = f1 / f2;
	
	string s = product.fractionToString();

	cout << s << endl;

	

	

	cin.get();
	return 0;
}

Fraction::Fraction()
{
	this->numerator = 0;
	this->denominator = 0;
}

Fraction::Fraction(int a, int b)
{
	this->numerator = a;
	this->denominator = b;
}

void Fraction::reduce()
{
	int a, b, r;
	a = (numerator);
	b = (denominator);
	if (a == 0)
	{
		numerator = 0;
		denominator = 1;
		return;
	}
	while (a != 0)
	if (a<b)
	{
		r = a; a = b; b = r;
		a = a - b;
	}
	int gcd = b;
	numerator = numerator / gcd;
	denominator = denominator / gcd;

}

int Fraction::GCD(int a, int b)
{
	while (a != b){
		if (b > a){
			b = b - a;
		}
		else { a = a - b; }
	}
	return a, b;
}


string Fraction::fractionToString()
{
	return to_string(numerator) + "/" + to_string(denominator);
}

[giblit]

Using this-> is a bit overkill. You would generally only need that when you want to do something like:

Fraction(int numerator, int denominator)
{
    this->numerator = numerator; //they are same
    //so only way to tell difference is with this->
    //...
}

[orangemexican]

ok got rid of this->

now how do i get the fractions to print reduced?

also when i tried to multiply f1*f2 i got the error: error C2676: binary '*' : 'Fraction' does not define this operator or a conversion to a type acceptable to the predefined operator

i made the main:

	Fraction f1(3,7);
	Fraction f2(4,8);
	Fraction product;
	Fraction quotient;

	product = f1*f2;
	
	quotient = f1 / f2;
	
	string s = product.fractionToString();

[giblit]

To print the reduced simply call your reduce function before returning the value.

string Fraction::fractionToString()
{
        reduce(); //reduce first
	return to_string(numerator) + "/" + to_string(denominator);
}

For those operations you have to overload them. You may want to check out these links to help get the understanding of operator overloading.
http://www.cplusplus.com/doc/tutorial/templates/
http://www.learncpp.com/ <--chapter 9