LNK2019

[veeyik]

Why i keep getting this error.
1>Programming6.3.obj : error LNK2019: unresolved external symbol "void __cdecl solveEquation(double &,double &)" (?solveEquation@@YAXAAN0@Z) referenced in function _main
Whats wrong with my code?

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;

void solveEquation(double &,double &);



int main ()
{	
	double k;
	double j;
	solveEquation(k,j);
	cout << k << j;

}



void solveEquation(double a, double b, double c, double d, double e, double f, double &x, double &y)
{

	cout << "Enter a,b,c,d,e,f: ";

	cin >> a,b,c,d,e,f;
x = (e*d - b* f)/(a*d - b*c);
y = (a*f - e* c)/(a*d-b*c);
}

[vlad from moscow]

The message is clear enough. The linker can not find the definition of function

void solveEquation(double &,double &);

You declared such function, call it in main but did not define it.

[Moschops]

As an aside, your function is nonsensical. You call the function with values of a, b, c, d, e, f, x and y... and then try to make the user input a, b, c, d, e, f anyway, overwriting the ones you passed in (except that you're using cin >> wrongly to do this and making a complete mess of it).

You need to learn:

1) Functions.
2) How to use cin.

[veeyik]

can u show me the correct way?

[vlad from moscow]

void solveEquation( double &x, double &y )
{
	double a, b, c, d, e, f;

	cout << "Enter a,b,c,d,e,f: ";

	cin >> a >> b >> c >> d >> e >> f;
	x = (e*d - b* f)/(a*d - b*c);
	y = (a*f - e* c)/(a*d-b*c);
}

[Catfish2]

void solveEquation(double &x, double &y)
{
    double a, b, c, d, e, f; // "local variables"

    cout << "Enter a, b, c, d, e, f: ";
    cin >> a >> b >> c >> d >> e >> f;
    x = (e*d - b* f)/(a*d - b*c);
    y = (a*f - e* c)/(a*d-b*c);
}

[Catfish2]

Damn you, vlad! Ha ha.

[veeyik]

But my question is like this:

http://imageshack.us/a/img341/555/questionx.jpg

[Moschops]

Then don't try to call the function like this:
solveEquation(k,j);

Call it like this:
solveEquation(a,b,c,d,e,f,x,y, isSolvable);

Do you understand that if you write the function to take in 9 parameters, as you have done and the question demands, when you call it you must pass in 9 parameters?

[veeyik]

Then i need to declare from a to f, x and y in my main func again?

[Catfish2]

Declare and read them too, in main().
Then your solveEquation() will be plain "muscle", with no cin and no cout.