void crt_wrt_cca(int c, int attr, int count, int page);
void crt_wrt_ca(int c, int attr, int page);
void crt_wrt_stra(const char *str, int count, int attr, int row, int col, int page);
void crt_wrt_cca(int c, int attr, int count, int page);
void crt_wrt_ca(int c, int attr, int page);
void crt_wrt_stra(const char *str, int count, int attr, int row, int col, int page);