Thread: no match for "operator+" problem!

Hello everyone, Im writing a fraction program that will do some nifty stuff. To cut to the chase, here are my 3 files but Im having trouble compiling the test function, i keep getting a "no match for 'operator+'" error. Thanks for all and any help!

fraction.h

Code:

#ifndef Fraction
#define Fraction

class mixedfraction
{
	public:
		mixedfraction();
		void read();
		void display();
		double evaluate();
		mixedfraction add (mixedfraction, mixedfraction);
		mixedfraction sub (mixedfraction);
		mixedfraction mul (mixedfraction);
		mixedfraction div (mixedfraction);
		int whole;
		int numerator;
		int denominator;
};
#endif

fraction.cpp

Code:

#include <iostream>
#include <cmath>
#include "mixedfraction.h"

using namespace std;

mixedfraction::mixedfraction()
{
	whole=0;
	numerator=0;
	denominator=1;
}

void mixedfraction::read()
{
	cout << "Please enter whole number: " <<endl;
	cin >> whole;
	cout << "Please enter numerator: " <<endl;
	cin >> numerator;
	cout << "Please enter denominator: " <<endl;
	cin >> denominator;
}

void mixedfraction::display()
{
	cout << whole << numerator <<"/" << denominator << endl;
}

double mixedfraction::evaluate()
{
	double temp;
	temp = (double) whole + (double) numerator / (double) denominator;
	return temp;
}

mixedfraction add (mixedfraction f1, mixedfraction f2)
{
	mixedfraction sum;
	sum.numerator = f1.numerator*f2.denominator + f2.numerator*f1.denominator;
	sum.denominator = f1.denominator*f2.denominator;
	return sum;
}

test.cpp

Code:

#include <iostream>
#include <cmath>
#include "mixedfraction.h"

using namespace std;

int main()
{
	mixedfraction x,y,z;
	double i;
	x.read();
	x.display();
	i = x.evaluate();
	cout << i << endl;
	y.read();
	y.display();
	z= x+y;
	cout << "The sum of ";
	x.display();
	cout << "and";
	y.display();
	cout << "is";
	z.display();
}

add should be like all the other methods you declared. Taking one argument makes more sense. Also, since this is c++ you should take advantage of operator overloading.

Originally Posted by wankel

thanks for the help guys!

changing it to "z = x.add(x, y);" worked. However, when I removed the second parameter, I get a compiling error:
mixedfractiontest.cpp:17: error: no matching function for call to ‘mixedfraction::add(mixedfraction&, mixedfraction&)’

Im sure I misunderstood what you guys were saying.

It should be x.add(y), if you want to add y to x.

Originally Posted by tabstop

It should be x.add(y), if you want to add y to x.

thanks tabstop. I made your change and both the fraction.cpp and fractiontest.cpp compile fine individually. But when I try to combine them using the following line on linux:

g++ -Wall -ggdb mixedfractiontest.o mixedfraction.o

I get this error:

mixedfractiontest.o: In function `main':
/home/atayh/Programs/mixedfractiontest.cpp:17: undefined reference to `mixedfraction::add(mixedfraction)'
collect2: ld returned 1 exit status

Im not sure what the problem could be since they compile just fine seperately =/

Thanks for the help and advice everyone! I finally got everything working nicely, but there is one last thing I would like some help on.

At the end of "test.cpp", how do I make z.display() the new x.read()? I have my program set up in a loop so when I get the sum of the addition, id like to use that new number as my default. I tried "x.read()=z.display()", but I got an error saying thats an invalid use of void. Is there another way to do this? Any help/tips/advice would be very much appreciated!