foo.cc: In function 'int main()':
foo.cc:7:15: warning: format '%f' expects a matching 'float*' argument [-Wformat=]
    7 |  scanf ("%f%f%f", &C, &F);
      |              ~^
      |               |
      |               float*
foo.cc:7:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |  scanf ("%f%f%f", &C, &F);
      |  ~~~~~~^~~~~~~~~~~~~~~~~~

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