View Compilation Error

0_0_39051578_11087.cpp: In function 'int f(int)':
0_0_39051578_11087.cpp:22:9: error: 'memset' was not declared in this scope
   22 |         memset(num, 0, sizeof(num));
      |         ^~~~~~
0_0_39051578_11087.cpp:2:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    1 | #include<iostream>
  +++ |+#include <cstring>
    2 | #define ll long long