Compilare: user.cpp: In function ‘int main()’: user.cpp:16:17: warning: format ‘%c’ expects argument of type ‘char*’, but argument 2 has type ‘int*’ [-Wformat=] scanf("%c",&nr); ^ user.cpp:8:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.in","r",stdin); ^ user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.out","w",stdout); ^ user.cpp:16:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&nr); ^