/in/foo.cc: In function 'int main()':
/in/foo.cc:10:2: error: 'else' without a previous 'if'
  else if(x==0)
  ^~~~
/in/foo.cc:10:7: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  else if(x==0)
       ^~
/in/foo.cc:12:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
   cout<<y<<endl;
   ^~~~
/in/foo.cc:14:2: error: 'else' without a previous 'if'
  else y=3*x*x;
  ^~~~