Move (and abstract) the random number functions to utils.c

src/trader.c

@@ -262,11 +262,8 @@ playing that game.  If GAME is not specified, start a new game.\n\n\
 
 void init_program (void)
 {
-    time_t curtime = time(NULL);    // NB: time_t may be larger than long int
-
-
     // Initialise the random number generator
-    srand48((long int) curtime);
+    init_rand();
 
     // Initialise the terminal display
     init_screen();

src/utils.c

@@ -260,3 +260,48 @@ void errno_exit (const char *format, ...)
 
     exit(EXIT_FAILURE);
 }
+
+
+/*-----------------------------------------------------------------------
+  Function:   init_rand  - Initialise the random number generator
+  Arguments:  (none)
+  Returns:    (nothing)
+
+  This function initialises the pseudo-random number generator.
+*/
+
+void init_rand (void)
+{
+    time_t curtime = time(NULL);    // NB: time_t may be larger than long int
+    srand48((long int) curtime);
+}
+
+
+/*-----------------------------------------------------------------------
+  Function:   randf   - Return a random number between 0.0 and 1.0
+  Arguments:  (none)
+  Returns:    double  - The random number
+
+  This function returns a pseudo-random number between 0.0 (inclusive)
+  and 1.0 (not inclusive) as a floating-point number.
+*/
+
+extern double randf (void)
+{
+    return drand48();
+}
+
+
+/*-----------------------------------------------------------------------
+  Function:   randi  - Return a random number between 0 and limit
+  Arguments:  limit  - Upper limit of random number
+  Returns:    int    - The random number
+
+  This function returns a pseudo-random number between 0 (inclusive) and
+  limit (not inclusive) as an integer.
+*/
+
+extern int randi (int limit)
+{
+    return randf() * (double) limit;
+}

src/utils.h

@@ -44,6 +44,8 @@
 *                     Utility function declarations                     *
 ************************************************************************/
 
+// Initialisation and environment functions
+
 extern void init_program_name (char *argv[]);
 extern const char *program_name (void);
 
@@ -52,10 +54,18 @@ extern const char *data_directory (void);
 
 extern char *game_filename (const int game_num);
 
+// Error-reporting functions
+
 extern void err_exit   (const char *format, ...)
     __attribute__((noreturn, format (printf, 1, 2)));
 extern void errno_exit (const char *format, ...)
     __attribute__((noreturn, format (printf, 1, 2)));
 
+// Random number functions
+
+extern void init_rand (void);
+extern double randf (void);
+extern int randi (int limit);
+
 
 #endif /* included_UTILS_H */