extern int vsprintf (const char *, const char *, va_list);
extern int puts(const char *);
extern char *gets(char *);
extern char getchar(void);
extern void putchar(char);
extern int vsprintf (const char *, const char *, va_list);
extern int puts(const char *);
extern char *gets(char *);
extern char getchar(void);
extern void putchar(char);