Compilare: user.cpp: In function ‘int main()’: user.cpp:24:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(a)-1;i++) ^ user.cpp:19:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reteta2.in", "r", stdin); ^ user.cpp:20:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reteta2.out", "w", stdout); ^ user.cpp:22:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a, Nmax, stdin); ^