Undefined symbol error??

Hi, I am doing a program that does all types of stuff with complex numbers. I think I have the code written correctly but keep getting an Undefined symbol error. It tells me sqrt and arctan and gives the file complex.o . I have #include <math.h> in my complex.c file and am using a makefile with the LIB of -lm. And everywhere I look, it says to do these things but they are already done. What could be wrong? I posted the code for the functions that use sqrt and arctan and maybe my syntax is just wrong.

Code:

---

#include <math.h>
          .
          .
          .
double MagCmplx(Cmplx z)
{
  /* Write this function */
  double m;

  m = sqrt(((z->x)*(z->x)) + ((z->y)*(z->y)));
return m;
}

double AngleCmplx(Cmplx z)
{
  /* Write this function */
  double theta;
  if((z->y)==0 && (z->x)>0)
    theta = 0;
  else if((z->y)==0 && (z->x)<0)
    theta = PI * (-1);
  else
    theta = arctan((z->x),(z->y));

return theta;
}

---

Please help!!! Thanks so much!

--Jacob

Quote:

---

Originally Posted by Jedijacob

Code:

---

#include <math.h>
          .
          .
          .
double MagCmplx(Cmplx z)
{
...

  m = sqrt(((z->x)*(z->x)) + ((z->y)*(z->y)));
...
}

double AngleCmplx(Cmplx z)
{
...
  if((z->y)==0 && (z->x)>0)
...
}

---

Please help!!! Thanks so much!

--Jacob

---

If z is a struct, its members are accessed with the '.' operator, not the '->' operator. So you would have something like this:

Code:

---

m = sqrt((z.x * z.x) + (z.y * z.y));

---

and

Code:

---

  if((z.y == 0) && (z.x > 0))

---

Regards,

Dave

You're probably specifying "-lm" in the wrong place. Searching libraries is order sensitive.

Example
gcc -lm prog.c
does not work

gcc prog.c -lm
does work

It's a linked list. We are studying unordered linked-list ADT's. Therefore, I am pretty sure we use the '->' instead of the '.' When I asked my instructor about the error he said that I probably capitalized it wrongly or misspelled it on accident or something like that but I don't see anything wrong with it at all!

--Jacob

Quote:

---

Originally Posted by Jedijacob

It's a linked list. We are studying unordered linked-list ADT's. Therefore, I am pretty sure we use the '->' instead of the '.' When I asked my instructor about the error he said that I probably capitalized it wrongly or misspelled it on accident or something like that but I don't see anything wrong with it at all!

--Jacob

---

I was assuming that Cmplx is a struct. (That's why I said, "If Cmplx is a struct.")

If it is a pointer to struct (has been typedef'ed to a pointer to struct), then you use '->'; If it is a struct (or has been typedef'ed to a struct) you use '.'

Since you didn't get compile errors complaining about struct operations, I see that my previous reply was not helpful. Sorry

I will note that arctan() is not part of the C standard libary, and is not prototyped in C standard header <math.h>

Unless you have defined this function somewhere, I suggest that maybe you could use the standard library function atan2(). (A final note: if you do mean to use atan2(), the order of arguments for atan2() is y, x.)


*edit* For my own edification, I would like to see the definition of Cmplx that you are using. Thanks


Regards,

Dave

Here is my definition of the struct.

Code:

---

typedef struct _cmplxCDT
{
  double x;
  double y;
}cmplxCDT;

---

Also, here is my makefile which I would think would be the problem but everything looks fine to me:

Code:

---

# Source, Executable, Includes, Library Defines
INCL  = complex.h
SRC    = complex.c complexfun.c
OBJ    = $(SRC:.c=.o)
LIBS  = -lm
EXE    = complexfun

# Compiler
CC    = gcc

# Compile and Assemble C Source Files into Object Files
.o:.c
        $(CC) -c  $(SRC)
# Link all Object Files with external Libraries into Binaries
$(EXE): $(OBJ)
        $(CC) -o $(EXE) $(OBJ) $(LIB)

# Objects depend on these Libraries
$(OBJ): $(INCL)

# Create a dbx Capable Executable with flags turned on
debug:
        $(CC) -Wall -g -DDEBUG -o $(EXE) $(LIBS)  $(SRC)

# Clean Up Objects, Exectuables, Dumps out of source directory
clean:
        rm -f $(OBJ) $(EXE) core

.SILENT :

---

Quote:

---

Originally Posted by Dave Evans

I would like to see the definition of Cmplx that you are using. Thanks

---

Quote:

---

Originally Posted by Jedijacob

Here is my definition of the struct.

Code:

---

typedef struct _cmplxCDT
{
  double x;
  double y;
}cmplxCDT;

---

---

That's not Cmplx, it's cmplxCDT.

Oh, sorry..this is in my interface file and I forgot about it:

Code:

---

typedef struct _cmplxCDT* Cmplx;

---

Code:

---

# Source, Executable, Includes, Library Defines
INCL  = complex.h
SRC    = complex.c complexfun.c
OBJ    = $(SRC:.c=.o)
LIBS  = -lm
EXE    = complexfun

# Compiler
CC    = gcc

# Compile and Assemble C Source Files into Object Files
.o:.c
        $(CC) -c  $(SRC)
# Link all Object Files with external Libraries into Binaries
$(EXE): $(OBJ)
        $(CC) -o $(EXE) $(OBJ) $(LIB)

# Objects depend on these Libraries
$(OBJ): $(INCL)

# Create a dbx Capable Executable with flags turned on
debug:
        $(CC) -Wall -g -DDEBUG -o $(EXE) $(LIBS)  $(SRC)

# Clean Up Objects, Exectuables, Dumps out of source directory
clean:
        rm -f $(OBJ) $(EXE) core

.SILENT :

---

Thanks a lot! It was that simple and I didn't even see it! Thanks for all your help. I might ask again later for some actual code help when I probably see my errors hehe! Thanks soo much again!!!

--Jacob