Compilare: user.cpp: In function ‘int main()’: user.cpp:16:22: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[255]’ [-Wformat=] scanf("%s\n", &a1); ^ user.cpp:17:20: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[255]’ [-Wformat=] scanf("%s", &a2); ^ user.cpp:14:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("puzzle.in","r",stdin); ^ user.cpp:15:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("puzzle.out","w",stdout); ^ user.cpp:16:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n", &a1); ^ user.cpp:17:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &a2); ^