Compilare: user.cpp: In function ‘int main()’: user.cpp:73:32: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘std::vector<ans>::size_type {aka long unsigned int}’ [-Wformat=] fprintf(fo,"%d\n", V.size()); ^ user.cpp:40:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d", &n); ^ user.cpp:44:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d", &x); ^