foo.cc: In function 'int main()':
foo.cc:8:1: warning: value computed is not used [-Wunused-value]
    8 | int (k=a/b);
      | ^~~~~~~~~~~
foo.cc:7:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 | scanf("%lf%lf",&a,&b);
      | ~~~~~^~~~~~~~~~~~~~~~

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