Compilare: user.cpp: In function ‘int main()’: user.cpp:58:32: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘std::vector<int>::size_type {aka long unsigned int}’ [-Wformat=] fprintf(fo,"%d\n", V.size()); ^ user.cpp:44:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m); ^ user.cpp:47:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &a, &b); ^