C language problem - I'm getting compiling error

[JoKKeR]

C language problem

Hi !

Im using function(s) before declaration. That is the reason im getting compiling error.

On the other hand reason why im using such program build is, that i like to keep things logical, at least on math level ( scientific equations).


So are there any techniques how to solve a problem im having ?

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

double L = 59.10; // latitude


double declination () //declination 583 539 87
{
       double d;
       d = declination(); //declination();
       double N = 0;
       
       N = 100;
       
       d = 23.45 * sin (360 / 365 * (284 + N)) ;

       return d;


    // d = declination
    //N = day number, January 1 = day 1


}

double hour_angle () // Hour angle 
{
       double Al;
       Al = altitude_angle() ;
       double L = L;
       double D;
       D = declination() ;
       double H = 0;
       double elev = 0;
       
       H = acos ( -1 * (sin (L) * sin (D) - sin (-0.8333 - 0.0347 *(sqrt (elev) ))) / (cos (L) * cos (D))) ;
       //H = cos-1[-1 * (sin (L) * sin (D) - sin (-0.8333 - 0.0347 (sqrt (elev)))) / (cos (L) * cos (D))] ;
       
       

    //Al = Solar altitude angle
    //L = Latitude (negative for Southern Hemisphere)
    //D = Declination (negative for Southern Hemisphere)
    //H = Hour angle

}

double altitude_angle () // Altidue angle 
{
       double Al = 0;
       double L = L;
       double D;
       D = declination() ;
       double H ;
       H = hour_angle() ;
       
       //sin(Al) =( cos(L) * cos(D) * cos(H)) + ( sin(L) * sin(D) ) ;
       Al =sin(( cos(L) * cos(D) * cos(H)) + ( sin(L) * sin(D) )) ;


    //Al = Solar altitude angle
    //L = Latitude (negative for Southern Hemisphere)
    //D = Declination (negative for Southern Hemisphere)
    //H = Hour angle


}

double azimuth_angle()
{
       
       double Az = 0;
       double Al;
       Al = altitude_angle() ;
       double L = L;
       double D;
       D = declination() ;
       
       
       
       //cos (Az) = (sin (Al) * sin (L) - sin (D)) / (cos (Al) * cos (L)) ;
        Az = cos((sin (Al) * sin (L) - sin (D)) / (cos (Al) * cos (L))) ;
       
       

    //Az = Solar azimuth angle
    //Al = Solar altitude angle
    //L = Latitude (negative for Southern Hemisphere)
    //D = Declination (negative for Southern Hemisphere)


}




double EOT () // Equation of time
{
       double N = 100;
       double B = 0;
       double E = 0;
       
       B = (360 * (N - 81)) / 365;
       
       E = (9.87 * sin(2*B)) - (7.53 * cos(B)) - (1.5 * sin(B));
       
       return E;
       
       //N = day number, January 1 = day 1 
}



int main()
{
 
  
  system("PAUSE");	
  return 0;
}

Thank you !

Added after 2 minutes:

BTW. The location of problem is between 2 or 3
function.

The variable Hour angle keep recurring .

 

[btbass]

Re: C language problem

The first function is recursive, it calls itself? A recursive function must have a termination state, I can not see one?
It gets worse!
The function 'hour_angle()' calls 'altitude_angle()' , which calls 'hour_angle()',
double recusion? And they both call the recursive function 'declination()'.
I wouldnt be surprised to see a wiff of smoke arise from the computer that tries to run this program.

 

[M!k]

Re: C language problem

concerning the order of functions use forward declaration:

#include <stdio.h> 
#include <stdlib.h> 
#include <math.h> 

// forward declaration of functions
double declination ();
double hour_angle ();
double altitude_angle ();
double azimuth_angle();
double EOT ();


double L = 59.10; // latitude 


double declination () //declination 583 539 87 
{ 
       double d; 
       d = declination(); //declination(); 
       double N = 0; 
        
       N = 100; 
        
       d = 23.45 * sin (360 / 365 * (284 + N)) ; 

       return d; 


    // d = declination 
    //N = day number, January 1 = day 1 


}

.
.
.

but it doesn't solve the problem with recursive functions that btbass mentioned...

 

[JoKKeR]

C language problem

Thank you for really good replies !

I guess my skill level is way basic, i need to gain more experience. cmon i worked on this code for a day ... there are actually pone number in comments

Ill try to re build whole thing, since i do not have much experience ... Can i have some advice how to combine many equations and link them to time resolution effect like thing.

Thank you !

 

[jhbbunch]

C language problem

What is d = declination() supposed to do other than put the program into a non-terminating loop and have the stack go rampaging through program memory until you get an 'out of memory' message? Also, I hope you realize that C programs start with main(), and not the first function defined in the source code, because your main() does nothing. It is probably a good practice to give all functions in a file a forward declaration, it makes the code more readable. Or better yet, put them in a header file and #include it at the top of the file.