Undefined symbol

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
#include <math.h>
#include <conio.h>
#include <stdio.h>
 
 
//---------------------------------------------------------------------------
 
#pragma argsused
typedef double (*TFun)(double);
 double s (double) ;
 double y(double) ;
 double f3(double )   ;
 void Out(TFun);
int main(int argc, char* argv[])
{
double a, b, h;
int n;
puts("Input a,b,h,n");        scanf("%lf%lf%lf%d", &a, &b, &h,&n);
puts("\n S(x)");    Out (s);
puts("\n Y(x)");    Out (y);
puts("\n |Y(x)-S(x)|"); Out (f3);
puts("\n Press any key ... ");
getch();
 
        return 0;
}
double s (double x,int n)
{
int k;
double r, sum;
r = sum = x;
        for (k = 1; k <= n; k++) {
            r = r * x *x / (2*k+1)/(2*k);
            sum += r;
        }
    return sum;
}
 
double y(double x)
{
        return sinh(x);
}
double f3(double x) { return fabs((s(x)-y(x))); }
 
 
 
void Out(TFun fun)
{
for (double x=a; x<=b; x+=h)
        printf(" x = %6.2lf, y = %8.4lf\n",x,fun(x));
}
 
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