Compilare: main.cpp: In function 'int main()': main.cpp:62:36: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::set<int>::size_type {aka long unsigned int}' [-Wformat=] fprintf (fout, "%d\n", st.size() ) ; ^ main.cpp:38:45: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d%d%d", &n, &m, &x, &y ) ; ^ main.cpp:40:35: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", &u, &v ) ; ^