Compilare: user.cpp: In function ‘int main()’: user.cpp:71:33: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 3 has type ‘std::set<std::pair<int, int> >::size_type {aka unsigned int}’ [-Wformat=] fprintf(g, "%ld\n", pos.size()); ^ user.cpp:12:12: warning: unused variable ‘m’ [-Wunused-variable] int n ,t, m; ^ user.cpp:17:21: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &t); ^ user.cpp:23:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d%s", &n, buffer); ^