foo.cc: In function 'int main()':
foo.cc:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |     scanf("%f,%f,%c",&a,&b,&c);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:24:8: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
   24 |  printf("%.2f",s);
      |  ~~~~~~^~~~~~~~~~

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