compilation - Problem compiling self-created header file using Dev-C++? -

i using dev-c++ on windows vista. have 3 files located in same directory. are:

- math_functions.h - math_functions.c - test3.c 

math_functions.h code:

int   sum       (int x, int y); float average   (float x, float y, float z); 

math_functions.c code:

int sum (int x, int y) {   return (x + y); }  float average (float x, float y, float z) {   return (x + y + z) / 3; } 

test3.c code:

#include <stdio.h> #include "math_functions.h"  main () {   int   thesum     = sum (8, 12);   float theaverage = average (16.9, 7.86, 3.4);    printf ("the sum is: %i ", thesum);   printf ("and average is: %f \n", theaverage);   printf ("average casted int is: %i \n", (int)theaverage); } 

it fails compile. error message is:

c:\users\esum\appdata\local\temp\cckmdaaa.o(.text+0x3a) in function `main':  [linker error] undefined reference `sum'  [linker error] undefined reference `average'  c:\users\esum\appdata\local\temp\cckmdaaa.o(.text+0x3a) ld returned 1 exit status  

i use same exact code compile in ubuntu(i run ubuntu using virtual machine i,e. vmplayer), compiled without errors.

do need set in dev-c++ compile files?

dev-c++ seems not linking math_function.c test3.c when making text3.exe configuration problem in dev-c++ need add math_function.c dev-c++ project