Compilare: user.cpp: In function ‘int main()’: user.cpp:81:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s2[p]=NULL; ^ user.cpp:38:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dist.in","r",stdin); ^ user.cpp:39:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dist.out","w",stdout); ^ user.cpp:41:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, MAXL, stdin); ^ user.cpp:57:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, MAXL, stdin); ^