Compilare: main.cpp: In function 'int main()': main.cpp:53:36: 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", tops.size()); ^ main.cpp: In function 'char nextch()': main.cpp:14:63: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] if (pos == BUF_SIZE) fread(buf, BUF_SIZE, 1, fin), pos = 0; ^