Ошибка компиляции. С++ функции

#include <iostream>
#include "func.h"
#include <windows.h>
using namespace std;
 
int main()
{
    double a, b, x, y, k;
    int Z;
    cout << "Enter x: "; cin >> x;
    cout << "Enter y: "; cin >> y;
    cout << "Enter k: "; cin >> k;
    cout << "Enter Z(integer): "; cin >> Z;
    func(a, b);
    cout << a << endl;
    cout << b << endl;
    return 0;
}

#include "func.h"
#include <cmath>
 
void func(double &a, double &b, double y, double x, double k, int Z)
{
    const double pi = 3.14;
    a = (pow(k, 1 / 4)) / x + (exp(y - 1)) / abs(5 * k + pow(x, 3)) - cos(Z * pi / 180) + tan(15 * 180 / pi);
    b = (10 + cbrt(pow(y, 5) + 2 * x)) + 4 / pow((3 * y - x), 3) + (pow(abs(y - x), 3)) / 3;
}

#pragma once
void func(double, double);

#include <iostream>
#include <cmath>
using namespace std;
 
double fa(double x)
{
    double pi = 3.14159265358979323846, q = x * x, c = cos(q);
    return cbrt(c * c * c + fabs(10. * x - 6.)) + sin(pi / 2.);
}
 
double fb(double x, double y)
{
    double eps = 1.e-9;
    double t = x / (x + fabs(8. * y * y * y));
    double s = x + y;
 
    if (fabs(t) < eps) t = 0.;
    if (t < 0. || s == 0.) throw "b not determined\nres not determined\n";
    double u = x * x + x * 10. * y / (s * s) + exp(5.);
    if (u > eps) return sqrt(t) - pow(u, 1. / 5.);
    else if (u < eps) return sqrt(t) + pow(-u, 1. / 5.);
    else return sqrt(t);
}
 
int main()
{
    double x, y;
    cout << "Enter x,y:\n";
    cin >> x >> y;
    try {
        double res = 13. * fa(x) - 10. * fb(x, y);
        cout << "b=" << fb(x, y) << "\n";
        cout << "result=" << res << "\n";
    }
    catch (char const* msg) {
        cout << msg;
    }
 
    system("pause");
    return 0;
}

    double x, y, a, b, res;
    cout << "Enter x,y:\n";
    cin >> x >> y;
    try {
        a=fa(x);
        b=fb(x,y);
        res=13.*a-10.*b*b;
        // cout << "b=" << b << "\n";
        cout << "result=" << res << "\n";
    }

double fb(double x, double y)
{
    double eps = 1.e-9;
    double t = x / (x + fabs(8. * y * y * y));
    double s = x + y;
 
    if (fabs(t) < eps) t = 0.;
    if (t < 0. || s == 0. || x + fabs(8. * y * y * y) == 0) throw "b not determined\nres not determined\n";
    double u = x * x + x * 10. * y / (s * s), e = exp(5.);
    if (u > eps) return sqrt(t) - pow(u, 1. / 5.) + e;
    else if (u < eps) return sqrt(t) + pow(-u, 1. / 5.) + e;
    else return sqrt(t) + e;
}

double fb (double x, double y)
{
    double z, s, t=0., eps=1.e-9;
    
    z=x+fabs(8.*y*y*y);
    if(z<=-eps || z>=eps) t=x/z;
    s=x+y;
    
    if(fabs(t)<eps) t=0.;
    
    if(fabs(z)<eps || t<0. || s==0.) throw "b not determined\nresult not determined\n";
    double u=x*x+x*10.*y/(s*s), e=exp(5.);
    if(u>eps) return sqrt(t)-pow(u,1./5.)+e;
    else if(u<eps) return sqrt(t)+pow(-u,1./5.)+e;
    else return sqrt(t)+e;
}