Help with methods of a fraction class

I'm doing this fraction arithmetic program, and have the following so far:

A Frac class with methods that allow for addition, subtraction, etc.
all of which crossmultiply for a common denominator, when necessary.

My problem is - I can't figure out how to code a function for reducing the results. I've got no idea what a systematic formula might look like. Could anyone help?

Oh, and I'm not supposed to use overloaded operators.

Code:

---

int reduce (int p, int q)
{
    int r;
    return ((r=p%q)==0)?  q : reduce (q,r);
}

---

then to call/reduce it

Code:

---

      int gcd
      gcd = reduce (num,denom);
      denom =/gcd;
      num =/ gcd;

---

oh yea
just make it a member of the class...
what i did, is have the displace function in the class do all the reducing, then displaying it

Much appriciated.

anytime

question: is this for a takehome test 3?

sounds exactly like something im doing for my class over spring break

Homework set 3. Probably from the same godawful book.

Because I'm such a noob, here's a few debug questions for all and sundry:

Basically...what the heck is wrong with my compiler? It won't recognize default args in the constructor, it's not recognizing the tilde as a destructor, and I'm passing functions with scope res operators, and when I call them in the main, it says it can't access the private parts of my class! My code seems pretty textbook, but Visual C++ is going nuts. Code is attatched.

with dev c++
u gottahave it public
not Public

this may be just me not knowing u can do this
but i didnt know u can pass it an arg and have it equal something

int a=1, int b=1, int c=1, int d=1, int e=1, int f=1
i dont think u can do that

there are a lot of small mistakes in ur code
like, having the prototype return type void
but the actual def return type int

i fixed all of ur little errors

Code:

---

//CIS 37
//Program Set #3
//
//Katherine Busch
//
//

#include <iostream.h>

class Frac {

                        int num1, num2, dem1, dem2, resnum, resdem;
                        float dec;
    public:
                    Frac(int a=1, int b=1, int c=1, int d=1, int e=1, int f=1);
                        ~Frac ();
                        int addFrac(/*int, int, int, int, int, int, float*/);
                        int subFrac(/*int, int, int, int, int, int, float*/);
                        int multFrac(/*int, int, int, int, int, int, float*/);
                        int divFrac(/*int, int, int, int, int, int, float*/);
                        int printFrac();
                        int printDec();
                        int reduce(int p, int q);

};

Frac::Frac(int a, int b, int c, int d, int e, int f)
{
        num1=a; num2=b; dem1=c; dem2=d; resnum=e; resdem=f;
       
}

Frac::~Frac()
{
        cout << "Destructed!"<<endl;
}

int Frac::printDec()
{
        cout << "Decimal results are: "<< dec << endl;
}

int Frac::reduce (int p, int q)
{
    int r;
    return ((r=p%q)==0)?  q : reduce (q,r);
}

int Frac::printFrac()
{
        cout << "Results are: "<< resnum<<"/"<<resdem<<endl;
}


int Frac::addFrac()
{
        if(dem1 != dem2)
                resdem = dem1 * dem2;
                resnum = (dem2 * num1) + (dem1 * num2);
       
}

int Frac::subFrac()
{
        if(dem1 != dem2)
       
                resdem = dem1 * dem2;
                resnum = (dem2 * num1) - (dem1 * num2);
       
}

int Frac::multFrac()
{
        resnum = num1 * num2;
        resdem = dem1 * dem2;
}

int Frac::divFrac()
{
        resnum = dem1 * num1;
        resdem = num1 * dem2;
}

main()
{
        Frac fraction (1, 3, 2, 5);
        fraction.addFrac();
        fraction.printFrac();
        fraction.printDec();

        fraction.subFrac();
        fraction.printFrac();
        fraction.printDec();

        fraction.multFrac();
        fraction.printFrac();
        fraction.printDec();

        fraction.divFrac();
        fraction.printFrac();
        fraction.printDec();

        return 0;
}

---

u gotta remember to make sure the function prototypes and the actual def match in return type as well as variables passed to it

u cant have something like

void foo ();

then have

int foo (int a)
{
}

also, for if statements, u dont need a semicolmn (sp)

just if (a!=b), not if (a !=b;)

oh yea, for the code
Frac(int a=1, int b=1, int c=1, int d=1, int e=1, int f=1);
in the constructor field in the class, im just mearly creating variables for it to use
i dunno if that works, but for now its compiling without error
and im sure ur going to want to take out the "=1"s and pass it values u want