Unresolved external "fun1 double"

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
#include <math.h>
#include <stdio.h>
#include <iostream.h>
#include <conio.h>
 
typedef double (*TFun)(double);
double fun1(double);
double fun2(double;
void Out_Rez (TFun,double,double,double);
 
//---------------------------------------------------------------------------
 
void main()
{
double a, b, h, x;
puts("Input a,b,h");                scanf("%lf%lf%lf", &a, &b, &h);
puts("\n\t Function - S(x)");   Out_Rez (fun1,a,b,h);
puts("\n\t Function - Y(x)");   Out_Rez (fun2,a,b,h);
puts("\n Press any key ... ");
getch ();
}
//---------- ---------------------------------
double fun1 (double f, double s, double k, double x, double n) {
s=0;
for(k=1;k<=n;k++) {
f=((pow(k,2)+1)/k)*pow(x/2,k);
s+=f; }
return s;
}
double fun2(double r, double x) {
        return (pow(x,2)/4+x/2+1)*exp(x/2);
}
void Out_Rez (TFun f,double xn,double xk,double h) {
    for(double x=xn; x<=xk; x+=h)
            printf(" x = %5.2lf, y = %8.4lf\n",x,f(x));
}
 
//---------------------------------------------------------------------------

double fun1 (double f, double s, double k, double x, double n);

double fun1(double);
double fun2(double;

//#include <vcl.h>
//#pragma hdrstop
#include <math.h>
#include <stdio.h>
#include <conio.h>
 
typedef double (*TFun)(double);
double fun1 (double);
double fun2(double);
void Out_Rez (TFun,double,double,double);
 
//---------------------------------------------------------------------------
const int n=10; // передаем в fun1 через глобальную переменную
void main()
{
double a, b, h;
puts("Input a,b,h");                scanf("%lf%lf%lf", &a, &b, &h);
puts("\n\t Function - S(x)");   Out_Rez (fun1,a,b,h);
puts("\n\t Function - Y(x)");   Out_Rez (fun2,a,b,h);
puts("\n Press any key ... ");
getch ();
}
//---------- ---------------------------------
double fun1 (double x)
{
    double s,f;
    int k;
    s=0;
    for(k=1;k<=n;k++) 
    {
        f=(k*k+1.0)/k*pow(x/2.,k);
        s+=f; 
    }
    return s;
}
double fun2(double x) 
{
        return (x*x/4.+x/2.+1.)*exp(x/2.);
}
void Out_Rez (TFun f,double xn,double xk,double h) {
    for(double x=xn; x<=xk; x+=h)
            printf(" x = %5.2lf, y = %8.4lf\n",x,f(x));
}