/in/foo.cc: In function 'int main()':
/in/foo.cc:5:37: warning: iteration 2 invokes undefined behavior [-Waggressive-loop-optimizations]
     for(int i = 0; i <= 2; i++)s[i] = getchar();
                                ~~~~~^~~~~~~~~~~
/in/foo.cc:5:22: note: within this loop
     for(int i = 0; i <= 2; i++)s[i] = getchar();
                    ~~^~~~
/in/foo.cc:6:5: warning: 's[2]' is used uninitialized in this function [-Wuninitialized]
     if(s[2] == '0'){
     ^~