foo.cc: In function 'int main()':
foo.cc:9:1: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
 if(op=='-')
 ^~
foo.cc:11:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  return 0;
  ^~~~~~