/in/foo.cc: In function 'int main()':
/in/foo.cc:9:44: warning: iteration 43u invokes undefined behavior [-Waggressive-loop-optimizations]
     for(int i=3;i<47;i++)f[i]=f[i-2]+f[i-1];
                                            ^
/in/foo.cc:9:18: note: containing loop
     for(int i=3;i<47;i++)f[i]=f[i-2]+f[i-1];
                  ^