Compilare: user.cpp: In function ‘int main()’: user.cpp:37:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &k, &q); ^ user.cpp:39:52: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%lld%lld", &n[1<<i], &r[1<<i]); ^ user.cpp:46:21: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] e[i]=e[b]^e[i^b]; ^