/in/foo.cc: In function 'bool a(std::string, std::string, std::string)':
/in/foo.cc:8:20: warning: left operand of comma operator has no effect [-Wunused-value]
    8 |     for(i=0,j=n-1;i<=n-1,j>=0;i++,j--){
      |                   ~^~~~~