foo.cc: In function 'int main()':
foo.cc:15:2: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
   15 |  else
      |  ^~~~
foo.cc:17:6: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'else'
   17 |      printf("%.2f",r);
      |      ^~~~~~
foo.cc:8:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |  scanf("%f,%f,%c",&op1,&op2,&op);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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