Compilare: main.cpp: In function 'int main()': main.cpp:28:41: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::set<std::pair<int, int> >::size_type {aka long unsigned int}' [-Wformat=] fprintf (g, "%d\n", s.size()); ^ main.cpp:10:27: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (f, "%d\n", &n); ^ main.cpp:14:38: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (f, "%d %d\n", &x, &y); ^