/in/foo.cc: In function 'int main()':
/in/foo.cc:6:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i <= sizeof(s);i++){
                ~~^~~~~~~~~~
/in/foo.cc:7:9: warning: iteration 100005 invokes undefined behavior [-Waggressive-loop-optimizations]
   if(s[i] == 'A'){
      ~~~^
/in/foo.cc:6:18: note: within this loop
  for(int i = 0;i <= sizeof(s);i++){
                ~~^~~~~~~~~~