8:38pm falcon  > cat mylib.h
typedef int Integer;

Integer function1 (Integer number);

Integer function2 (Integer number);

8:38pm falcon  > cat func1.c
#include "mylib.h"

Integer function1 (Integer number)
{
        return number + 1;
}

8:38pm falcon  > cat func2.c
#include "mylib.h"

Integer function2 (Integer number)
{
        return number - 1;
}

8:38pm falcon  > cat mylib_client.c 
#include <stdio.h>
#include <stdlib.h>
#include "mylib.h"


int main(void)
{
   int number = 10; 
   printf("number incremented is %d.\n ", function1(number));
   printf("number decremented is %d.\n ", function2(number));
   printf(" f(4) is %d.\n ", function2(4));

   return 0;
}
8:38pm falcon  > gcc -c -Wall -ansi -pedantic func1.c
8:38pm falcon  > gcc -c -Wall -ansi -pedantic func2.c
8:38pm falcon  > gcc -c -Wall -ansi -pedantic mylib_client.c 
8:38pm falcon  > gcc *.o
8:38pm falcon  > a.out
number incremented is 11.
 number decremented is 9.
  f(4) is 3.
 8:38pm falcon  >