/in/foo.cc: In function 'int main()':
/in/foo.cc:6:6: warning: suggest parentheses around comparison in operand of '==' [-Wparentheses]
  s[0]==a[0]==0;
  ~~~~^~~~~~
/in/foo.cc:6:12: warning: statement has no effect [-Wunused-value]
  s[0]==a[0]==0;
  ~~~~~~~~~~^~~