Compilare: user.cpp: In function ‘int main()’: user.cpp:29:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d%d", &n, &a, &b); ^ user.cpp:32:42: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &x[i], &y[i]); ^ user.cpp:52:30: warning: ‘last’ may be used uninitialized in this function [-Wmaybe-uninitialized] vf=last-1; ^