foo.cc: In function 'int main()':
foo.cc:5:9: error: 'cin' was not declared in this scope
    5 |         cin>>a>>y>>o;
      |         ^~~
foo.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;
foo.cc:7:9: error: 'printf' was not declared in this scope
    7 |         printf("%.1f",k);
      |         ^~~~~~
foo.cc:1:1: note: 'printf' is defined in header '<cstdio>'; did you forget to '#include <cstdio>'?
  +++ |+#include <cstdio>
    1 | using namespace std;

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