C++

Forum

 
My code doesn't compile

dangkhanhlinh (2)
Hi everybody,

I have a code which I don't compile. This code is :

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
 
 //====================LIBRARY===================================================
#include <stdio.h>
#include <math.h>
#include <conio.h>
#define EPS 3.0e-14
#define MAXIT 10
//====================MAIN======================================================
double q,dk;
double ftest_k(double k);
double test();
void gaulegf(double x1, double x2, double x[], double w[], int n);
int main()
{ 
  FILE *output;
  output=fopen ("testtp.dat","w+" );
  printf(" %f\n  ",test()); 
  fprintf(output, " %f\n",test());
  fclose(output);
  printf("\nfin\n");
  getch();
}
//====================THE TEST FUNCTION===============================
void gaulag(float x[],float w[],int n,float alf)
{
	float gammln(float xx);
	void nrerror(const char error_text[]);
	int i,its,j;
	float ai;
	double p1,p2,p3,pp,z,z1;

	for (i=1;i<=n;i++) {
		if (i == 1) {
			z=(1.0+alf)*(3.0+0.92*alf)/(1.0+2.4*n+1.8*alf);
		} else if (i == 2) {
			z += (15.0+6.25*alf)/(1.0+0.9*alf+2.5*n);
		} else {
			ai=i-2;
			z += ((1.0+2.55*ai)/(1.9*ai)+1.26*ai*alf/
				(1.0+3.5*ai))*(z-x[i-2])/(1.0+0.3*alf);
		}
		for (its=1;its<=MAXIT;its++) {
			p1=1.0;
			p2=0.0;
			for (j=1;j<=n;j++) {
				p3=p2;
				p2=p1;
				p1=((2*j-1+alf-z)*p2-(j-1+alf)*p3)/j;
			}
			pp=(n*p1-(n+alf)*p2)/z;
			z1=z;
			z=z1-p1/pp;
			if (fabs(z-z1) <= EPS) break;
		}
		if (its > MAXIT) nrerror(" too many iterations in gaulag ");
		x[i]=z;
		w[i] = -exp(gammln(alf+n)-gammln((float)n))/(pp*n*p2);
	}
}
#undef EPS
#undef MAXIT
double ftest_k(double k) 
{ double kq;
  kq=k;
  return kq;
}
double test()
{
  int n,i, j;
  double sum;
  float k[2000], w[2000], alf;
  i=100.;
    gaulag(k, w, n, alf);
    sum = 0.0;
    for(j=1; j<=i; j++)
    {
      sum = sum + w[j]*ftest_k(k[j]);
    }
  return sum;  
}


Would you mind helping me to compile this code. Thanks so much.
Last edited on
keskiverto (10365)
When something "don't compile", the compiler or the linker does tell why it does not. Show what they say.
dangkhanhlinh (2)
This code is in C. So, I tried to change this code from C to C++. I use Dev-C++ 5.11 to compile. It told that undefined reference to 'nrerror(char const*)' , undefined reference to 'gammln(float)' . Please help me.
MikeyBoy (5631)
1) Please use code tags when posting code, to make it readable:

http://www.cplusplus.com/articles/z13hAqkS/

2) Where have you defined those functions? I don't see definitions for them anywhere in the code you've posted.
keskiverto (10365)
Compile C code with a C compiler. The C++, while close, can differ.

undefined reference

is a linker error. We have to give to the linker all necessary object code so that it can link an executable together. Some of the object code is in the object files that we compile from source code, some within libraries that others have compiled.

If you don't have the implementation of nrerror(char const*) anywhere, then you should add it.
Topic archived. No new replies allowed.