foo.cc: In function 'int main()':
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",&x,&y,&op);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:25:8: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   25 |  printf("%.2f",r);
      |  ~~~~~~^~~~~~~~~~

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