Compilare: user.cpp: In function ‘int main()’: user.cpp:61:33: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 3 has type ‘std::vector<int>::size_type {aka unsigned int}’ [-Wformat=] fprintf(out, "%ld\n", S.size()); ^ user.cpp:49:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &N, &M); ^ user.cpp:55:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &x, &y); ^