Undefined reference error? Rational class lab

[ryan157]

Why does my code give me this error when I try to compile it?

"/tmp/cciZVFen.o: In function `main':
Lab6rational.cpp:(.text+0x22): undefined reference to `rational::rational()'
Lab6rational.cpp:(.text+0x2e): undefined reference to `rational::rational()'
Lab6rational.cpp:(.text+0x3a): undefined reference to `rational::rational()'
Lab6rational.cpp:(.text+0x55): undefined reference to `rational::read()'
Lab6rational.cpp:(.text+0x70): undefined reference to `rational::read()'
Lab6rational.cpp:(.text+0x7f): undefined reference to `rational::sum(rational, rational)'
Lab6rational.cpp:(.text+0x9e): undefined reference to `rational::write()'
Lab6rational.cpp:(.text+0xf2): undefined reference to `rational::get_numerator()'
Lab6rational.cpp:(.text+0x10d): undefined r"


If anyone knows any help is appreciated!!!

  #include <iostream> 
using namespace std; 

// Add appropriate headers

/*  KEEP THIS COMMENT
* class Rational
*    represents a Rational number. Remember rational means ratio-nal
*    which means there is a numerator and denominator having
*    integer values. Using good ADT techniques, we have made member
*    variable private (also known as instance variables) and made member
*    functions public.
*/

class rational
{
    public: 
	// ToDo: Constructor that takes int numerator and int denominator
        rational(int numerator, int denominator);
	// ToDo: Constructor that takes int numerator
        rational(int numerator);
	// ToDo: Default Constructor
        rational();
	// ToDo: Member function to read a rational in the form: n/d
        void read();
         
	// ToDo: Member function to write a rational as n/d 
        void write();
        
        
	// ToDo: declare an accessor function to get the numerator
        int get_numerator();
	// ToDo: declare an accessor function to get the denominator
        int get_denominator();
	// ToDo: delcare a function called Sum that takes two rational objects
	    void sum (rational rat1, rational rat2);
	    
	    
	// sets the current object to the sum of the given objects using the
	// formula: a/b + c/d = ( a*d + b*c)/(b*d)
        

};
//void rational::input()
// char c;
// cin >> numerator >> c >> denominator; 


//rational3.sum(rational1,rational2);

int main()
{
	// ToDo: declare three rational objects using the default constructor
	
    rational rat1,rat2,rat3;
	char answer;

	// Main loop to read in rationals and compute the sum
	do {
		cout << "\nEnter op1 (in the format of p/q): ";
		
		// ToDo: use your input member function to read the first rational;;;;
		 rat1.read();

		cout << "\nEnter op2 (in the format of p/q): ";
		// ToDo: use your input member function to read the second rational
		 rat2.read();

		// ToDo: use the third rational to call Sum with first and second as parameters
	     rat3.sum(rat1,rat2);
         
		cout << "\nThe sum of op1 and op2 is: ";
		// ToDo: ouptput the third rational
	      rat3.write();

		cout << "\nTry again (Y/N)?";
		cin >> answer;

	} while (answer == 'y' || answer == 'Y');

	// ToDo: test getters 
	cout << "\nC's numerator is: " ;
    rat3.get_numerator();

	cout << "\nC's denominator is: ";
    rat3.get_denominator();
    
	return 0;
}

// ToDO: Implement your class member functions below. 

[Satan]

You never defined the functions under the class.. how is the compiler supposed to know what you want to happen?

You're supposed to fill the helper functions yourself so have a go at it. You haven't written them in that program, you probably didn't realize.