Advanced C Programming
                                           Spring 2004


   Excercise 12 (Variable lenght parameter list)
         
         Write a function that displays all strings passed as a 
         parameter. C-strings are allways passed as a pointer as
         you remember. In this case we pass a NULL pointer as a
         last parameter to indicate that there is no more strings.


         The following example calls demonstrates how the function 
         is used

              display_strings(NULL);           //Nothing is displayed
              display_strings("abc", NULL);    //abc is displayed
              display_strings("abc", "defgh", NULL);
                                               //two strings are displayed
              display_strings("abc", "defgh", "hijklmn", NULL); 
                                               //three strings are displayed
              display_strings("abc", "defgh", "hijklmn", "opqrstuvxyz", NULL); 
                                               //four strings are displayed

                           

         Remark 1. Inside the implementation of display_strings use 
         function puts (not printf with format specifier %s). The reason 
         for this is that then the compiler gives you an error message 
         if you try to pass a parameter that is not of type char *. 
         Type char * is the type of each separate string of course. 
         
         Remark 2. As you saw in a class, you don't need an assembly language
         to complete this task.         
         
         Remark 3. There is no need to use tools in <stdarg.h>.

         Remark 4. The function that concatenates all strings would be more
         useful in real programming situations. Instead of the simplified 
         function above, you can write this kind of more useful function if
         you like. Anyway, the function above demonstrates the basic idea.