foo.cc: In function 'int main()':
foo.cc:14:29: error: 'strlen' was not declared in this scope
   14 |         for (int j = 0; j < strlen(a); j++)
      |                             ^~~~~~
foo.cc:3:1: note: 'strlen' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    2 | #include <string>
  +++ |+#include <cstring>
    3 | using namespace std;
foo.cc:25:29: error: 'strlen' was not declared in this scope
   25 |         for (int i = 0; i < strlen(s)-sum; i++)
      |                             ^~~~~~
foo.cc:25:29: note: 'strlen' is defined in header '<cstring>'; did you forget to '#include <cstring>'?

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