C++ to C translation

Hi,

I've got a C++ file with a function I want to use - whatconstel (pp, epoch).

I've tryied to call it from my main program and compile - but it gives «hundreds of errors». First, I don't know how to declare it; secondo how to call it; third, how to translate it.
The code is this:

#include "precess.c";
/*precess - this routine is already made and functioning*/
#include <stdio.h>
#if __STDC__
static int islow (char *);
static int isup (char *);
static int isnumber (char *);
static int skipwh(char *);
double sqrt (double);
double sin (double);
double cos (double);
double atan2 (double, double);
double asin (double);
int precess (double *, double, int);
#else
static int islow(), isup(), isnumber(), skipwh();
double sqrt(), sin(), cos(), atan2(), asin();
int precess();
#endif

#define RTD 57.295779513082320877

#define NCON 89
char *constel[NCON] = {
"And Andromedae",
(etc...)
"Vul Vulpeculae",
};



/* Greek letters
*/

#define NGREEK 24
char *greek[NGREEK] = {
"alpha",
(etc...)
"omega",
};

int showcname( in )
char *in;
{
char *g, *p, *q;
char ans[80];
int i;


p = in;
q = ans;


skipwh(p);
if( isnumber(p) )
{
while( isnumber(p) )
*q++ = *p++;
}
skipwh(p);
*q++ = ' ';

if( islow(p) )
{
for( i=0; i<NGREEK; i++ )
{
g = greek[i];
if( (*p == *g) && (*(p+1) == *(g+1)) )
break;
}
if( i < NGREEK )
{
while( *g != '\0' )
*q++ = *g++;
}
while( islow(p) )
++p;
}
skipwh(p);
/* copy things like "-a" until uppercase letter found */
while( (*p != '\0') && !isup(p) )
*q++ = *p++;

*q++ = ' ';

if( isup(p) )
{
/* Check the list of constellation names */
for( i=0; i<NCON; i++ )
{
g = constel[i];
if( (*p == *g) && ( *(p+1) == *(g+1) )
&& ( *(p+2) == *(g+2) ) )
break;
}
/* Get the name found */
if( i < NCON )
{
g += 4;
while( *g != '\0' )
*q++ = *g++;
p += 3;
}
}
skipwh(p);
*q++ = ' ';
while( *p )
*q++ = *p++;
*q++ = '\0';
/* convert all '_' characters to spaces */
q = ans;
while( *q != '\0' )
{
if( *q == '_' )
*q = ' ';
++q;
}
printf( "\n %s\n", ans );
return(0);
}




static int islow(p)
char *p;
{
if( (*p >= 'a') && (*p <= 'z') )
return(1);
else
return(0);
}



static int isup(p)
char *p;
{
if( (*p >= 'A') && (*p <= 'Z') )
return(1);
else
return(0);
}




static int isnumber(p)
char *p;
{
if( (*p >= '0') && (*p <= '9') )
return(1);
else
return(0);
}



static int skipwh(p)
char *p;
{
while( ((*p == ' ') || (*p == '\t') || (*p == '_'))
&& (*p != '\0') && (*p != '\n') && (*p != '\r') )
++p;
return(0);
}



#define NBNDRIES 357
long bndries[4*NBNDRIES] = {
0L, 86400L, 316800L, 84L,
(etc...)
0L, 86400L, -324000L, 58L,
};


char *
whatconstel (pp, epoch)
double pp[];
double epoch;
{
int i, k;
double ra, dec, d;
double p[3];

for (i = 0; i < 3; i++)
p[i] = pp[i];

precess (p, epoch, 1);
precess (p, 2405889.25855, -1);
d = p[0] * p[0] + p[1] * p[1] + p[2] * p[2];
d = sqrt (d);
ra = atan2 (p[1], p[0]) * (RTD * 3600. / 15.);
if (ra < 0.0)
ra += 86400.0;
dec = asin (p[2] / d) * (RTD * 3600.);

for (i = 0; i < NBNDRIES; i++)
{
k = i << 2;
if (ra >= bndries[k] && ra < bndries[k+1] && dec > bndries[k+2])
{
k = (int) bndries[k+3];
return (constel[k]);
}
}
return ("?? constellation not found");
}

#if 0
/* Test program */
double J2000 = 2451545.0;
double STR = 4.8481368110953599359e-6;

test (r,d)
double r, d;
{
double c, p[3], jd;

d /= RTD;
r *= 15.0/RTD;
c = cos(d);
p[2] = sin(d);
p[0] = c * cos(r);
p[1] = c * sin(r);
jd = 2433282.423; /* 1950.0 Besselian epoch */
printf ("%8.4f %9.4f %s\n", r, d, whatconstel (p, jd));
}


int
main()
{
/* The following is an example of the output of the program:
RA = 9.0000 DEC = 65.0000 IS IN CONSTELLATION UMa
RA = 23.5000 DEC = -20.0000 IS IN CONSTELLATION Aqr
RA = 5.1200 DEC = 9.1200 IS IN CONSTELLATION Ori
RA = 9.4555 DEC = -19.9000 IS IN CONSTELLATION Hya
RA = 12.8888 DEC = 22.0000 IS IN CONSTELLATION Com
RA = 15.6687 DEC = -12.1234 IS IN CONSTELLATION Lib
RA = 19.0000 DEC = -40.0000 IS IN CONSTELLATION CrA
RA = 6.2222 DEC = -81.1234 IS IN CONSTELLATION Men */
test (9.0, 65.0);
test (23.5, -20.0);
test (5.12, 9.12);
test (9.4555, -19.9);
test (12.8888, 22.0);
test (15.6687, -12.1234);
test (19.0, -40.0);
test (6.2222, -81.1234);
exit(0);
}
#endif


Can someone help me translate the little differences that might exist, and tell me how to use this file in my main program?

Thanks in advance.

Regards,

Kepler

Please read the post for new users and put code tags around your code to preserve the indentation. It's right at the top of the forum, says READ THIS FIRST.

what let you believe it's a c++ progr ?
i find, it's a very worst writted (K&R style, NOT ansi)
essay for a 'c' code.
i did not study it, scanning it i saw errors, globals ...
sure it does not run.
i will&&can not believe, about 40 years after K&R,
that's the level of modern 'c' (+= other) programmers.

probably some very very old code he dug out of a book or online. I hope schools don't teach that style any more

Global declarations are perhaps infelicitous, but there's a qualitative distinction between error and poor judgement.