foo.cc: In function 'int main()':
foo.cc:10:29: warning: format '%d' expects argument of type 'int*', but argument 4 has type 'double*' [-Wformat=]
  scanf("%lf %lf %d",&a,&b,&n);
                           ~~^
foo.cc:11:22: warning: field precision specifier '.*' expects argument of type 'int', but argument 2 has type 'double' [-Wformat=]
  printf("%.*lf",n,a/b);}
                      ^
foo.cc:6:18: warning: unused variable 'e' [-Wunused-variable]
     double a,b,n,e;
                  ^
foo.cc:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lf %lf %d",&a,&b,&n);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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