Compilare: user.cpp: In function ‘int main()’: user.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x>=f[i]){ ~^~~~~~ user.cpp:21:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&q); ^ user.cpp:23:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%llu",&x); ^ user.cpp:18:13: warning: iteration 78 invokes undefined behavior [-Waggressive-loop-optimizations] f[i]=f[i-1]+f[i-2]; ~~~~^~~~~~~~~~~~~~ user.cpp:17:15: note: within this loop for (i=2;i<=80;i++) ~^~~~