/in/foo.cc: In function 'int main()':
/in/foo.cc:13:11: error: 'strlen' was not declared in this scope
   13 | for(i=0;i<strlen(a);i++)
      |           ^~~~~~
/in/foo.cc:2:1: note: 'strlen' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    1 | #include<iostream>
  +++ |+#include <cstring>
    2 | using namespace std;
/in/foo.cc:11:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 | scanf("%s",a) ;
      | ~~~~~^~~~~~~~