Compilare: user.cpp: In function ‘int main()’: user.cpp:47:10: warning: variable ‘a’ set but not used [-Wunused-but-set-variable] char a; ^ user.cpp:45:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(si,"%i %i",&n,&m); ^ user.cpp:55:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,2005,si); ^