foo.cc: In function ‘int main()’:
foo.cc:4:9: error: ‘scanf’ was not declared in this scope
    4 |         scanf("%d",&a);
      |         ^~~~~
foo.cc:15:9: error: ‘printf’ was not declared in this scope
   15 |         printf("%d",c);
      |         ^~~~~~
foo.cc:1:1: note: ‘printf’ is defined in header ‘<cstdio>’; did you forget to ‘#include <cstdio>’?
  +++ |+#include <cstdio>
    1 | int main()