foo.cc: In function ‘int main()’:
foo.cc:9:5: error: ‘memset’ was not declared in this scope
    9 |     memset(f, 0, sizeof(f));
      |     ^~~~~~
foo.cc:1: note: ‘memset’ is defined in header ‘<cstring>’; this is probably fixable by adding ‘#include <cstring>’
    1 | #include<iostream>