Compilare: user.cpp: In member function ‘const int number::operator+=(number&)’: user.cpp:20:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1;i < a.nr.size() || i < nr.size() || rest;i++) { ^ user.cpp:20:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1;i < a.nr.size() || i < nr.size() || rest;i++) { ^ user.cpp:23:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i >= a.nr.size()) ^ user.cpp:25:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i >= nr.size()) ^ user.cpp:33:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In member function ‘const int number::operator=(number&)’: user.cpp:36:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:42:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &n); ^